From 5211f48ae3cc0d87a260dbf5c3ab8bdae664c4b6 Mon Sep 17 00:00:00 2001
From: Russell Keith-Magee <russell@keith-magee.com>
Date: Tue, 4 May 2010 14:00:30 +0000
Subject: [PATCH] Fixed #12164 -- Removed the Python 2.3 compatibility imports
 and workarounds. Thanks to timo and claudep for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13094 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/contrib/admin/actions.py               |    4 -
 django/contrib/admin/options.py               |    4 -
 django/contrib/admin/sites.py                 |    4 -
 django/contrib/admin/views/decorators.py      |    2 +-
 django/contrib/admin/views/main.py            |    5 -
 django/contrib/auth/backends.py               |    5 -
 django/contrib/auth/decorators.py             |    2 +-
 django/contrib/formtools/utils.py             |    2 +-
 django/contrib/localflavor/br/forms.py        |    5 -
 django/contrib/messages/storage/fallback.py   |    5 -
 django/core/cache/backends/locmem.py          |    2 +-
 django/core/management/base.py                |    5 -
 django/core/management/sql.py                 |    5 -
 django/core/serializers/json.py               |    6 +-
 django/core/urlresolvers.py                   |    6 -
 django/db/backends/creation.py                |    5 -
 django/db/backends/oracle/base.py             |    5 +-
 django/db/backends/sqlite3/base.py            |    2 +-
 django/db/backends/util.py                    |    6 +-
 django/db/models/fields/__init__.py           |    2 +-
 django/db/models/options.py                   |    4 -
 django/db/transaction.py                      |    2 +-
 django/dispatch/dispatcher.py                 |    4 -
 django/forms/models.py                        |    5 -
 django/template/defaultfilters.py             |    9 +-
 django/template/defaulttags.py                |    3 +-
 django/test/simple.py                         |    8 -
 django/utils/_decimal.py                      | 3079 -----------------
 django/utils/decorators.py                    |    2 +-
 django/utils/encoding.py                      |    7 +-
 django/utils/functional.py                    |    8 +-
 django/utils/itercompat.py                    |   58 +-
 django/views/decorators/cache.py              |    2 +-
 django/views/decorators/csrf.py               |    2 +-
 django/views/decorators/http.py               |    2 +-
 django/views/decorators/vary.py               |    2 +-
 tests/modeltests/aggregation/models.py        |   10 +-
 tests/modeltests/basic/models.py              |   12 -
 tests/modeltests/model_formsets/models.py     |    5 -
 tests/modeltests/or_lookups/models.py         |    5 -
 tests/modeltests/serializers/models.py        |    6 +-
 .../management/commands/app_command.py        |    5 -
 .../management/commands/base_command.py       |    5 -
 .../management/commands/label_command.py      |    5 -
 .../management/commands/noargs_command.py     |    5 -
 .../aggregation_regress/models.py             |    5 -
 tests/regressiontests/decorators/tests.py     |    2 +-
 tests/regressiontests/defaultfilters/tests.py |    6 -
 tests/regressiontests/forms/extra.py          |    5 +-
 tests/regressiontests/forms/fields.py         |    6 +-
 tests/regressiontests/forms/forms.py          |    5 +-
 tests/regressiontests/forms/widgets.py        |    5 +-
 tests/regressiontests/model_fields/models.py  |    5 -
 tests/regressiontests/model_fields/tests.py   |    7 +-
 .../model_inheritance_regress/models.py       |    6 -
 tests/regressiontests/queries/models.py       |   12 +-
 tests/regressiontests/utils/itercompat.py     |   15 -
 tests/regressiontests/utils/tests.py          |    9 -
 tests/runtests.py                             |    6 -
 59 files changed, 32 insertions(+), 3399 deletions(-)
 delete mode 100644 django/utils/_decimal.py
 delete mode 100644 tests/regressiontests/utils/itercompat.py

diff --git a/django/contrib/admin/actions.py b/django/contrib/admin/actions.py
index 69374626cc0..b75c91b75ab 100644
--- a/django/contrib/admin/actions.py
+++ b/django/contrib/admin/actions.py
@@ -12,10 +12,6 @@ from django.utils.html import escape
 from django.utils.safestring import mark_safe
 from django.utils.text import capfirst
 from django.utils.translation import ugettext_lazy, ugettext as _
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
 
 def delete_selected(modeladmin, request, queryset):
     """
diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index 6334a311da0..1f8ff6dbd18 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -23,10 +23,6 @@ from django.utils.text import capfirst, get_text_list
 from django.utils.translation import ugettext as _
 from django.utils.translation import ungettext, ugettext_lazy
 from django.utils.encoding import force_unicode
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
 
 HORIZONTAL, VERTICAL = 1, 2
 # returns the <ul> class for a given radio_admin field
diff --git a/django/contrib/admin/sites.py b/django/contrib/admin/sites.py
index acaceb4ac4d..44464904510 100644
--- a/django/contrib/admin/sites.py
+++ b/django/contrib/admin/sites.py
@@ -14,10 +14,6 @@ from django.utils.text import capfirst
 from django.utils.translation import ugettext_lazy, ugettext as _
 from django.views.decorators.cache import never_cache
 from django.conf import settings
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
 
 ERROR_MESSAGE = ugettext_lazy("Please enter a correct username and password. Note that both fields are case-sensitive.")
 LOGIN_FORM_KEY = 'this_is_the_login_form'
diff --git a/django/contrib/admin/views/decorators.py b/django/contrib/admin/views/decorators.py
index fc8582b1b82..afdc07589d7 100644
--- a/django/contrib/admin/views/decorators.py
+++ b/django/contrib/admin/views/decorators.py
@@ -2,7 +2,7 @@ import base64
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from django import http, template
 from django.conf import settings
diff --git a/django/contrib/admin/views/main.py b/django/contrib/admin/views/main.py
index d34bb1b1951..8c09c10ab31 100644
--- a/django/contrib/admin/views/main.py
+++ b/django/contrib/admin/views/main.py
@@ -9,11 +9,6 @@ from django.utils.translation import ugettext
 from django.utils.http import urlencode
 import operator
 
-try:
-    set
-except NameError:
-    from sets import Set as set   # Python 2.3 fallback
-
 # The system will display a "Show all" link on the change list only if the
 # total result count is less than or equal to this setting.
 MAX_SHOW_ALL_ALLOWED = 200
diff --git a/django/contrib/auth/backends.py b/django/contrib/auth/backends.py
index bcfd5326649..9d674664ebc 100644
--- a/django/contrib/auth/backends.py
+++ b/django/contrib/auth/backends.py
@@ -1,8 +1,3 @@
-try:
-    set
-except NameError:
-    from sets import Set as set # Python 2.3 fallback
-
 from django.db import connection
 from django.contrib.auth.models import User, Permission
 
diff --git a/django/contrib/auth/decorators.py b/django/contrib/auth/decorators.py
index 50c09247b8a..09dcf42e42a 100644
--- a/django/contrib/auth/decorators.py
+++ b/django/contrib/auth/decorators.py
@@ -1,7 +1,7 @@
 try:
     from functools import update_wrapper, wraps
 except ImportError:
-    from django.utils.functional import update_wrapper, wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import update_wrapper, wraps  # Python 2.4 fallback.
 
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.http import HttpResponseRedirect
diff --git a/django/contrib/formtools/utils.py b/django/contrib/formtools/utils.py
index 44b8de1188b..e77931ffbac 100644
--- a/django/contrib/formtools/utils.py
+++ b/django/contrib/formtools/utils.py
@@ -32,7 +32,7 @@ def security_hash(request, form, *args):
     data.append(settings.SECRET_KEY)
 
     # Use HIGHEST_PROTOCOL because it's the most efficient. It requires
-    # Python 2.3, but Django requires 2.3 anyway, so that's OK.
+    # Python 2.3, but Django requires 2.4 anyway, so that's OK.
     pickled = pickle.dumps(data, pickle.HIGHEST_PROTOCOL)
 
     return md5_constructor(pickled).hexdigest()
diff --git a/django/contrib/localflavor/br/forms.py b/django/contrib/localflavor/br/forms.py
index 9f482cd01fd..7a7a8587798 100644
--- a/django/contrib/localflavor/br/forms.py
+++ b/django/contrib/localflavor/br/forms.py
@@ -10,11 +10,6 @@ from django.utils.encoding import smart_unicode
 from django.utils.translation import ugettext_lazy as _
 import re
 
-try:
-    set
-except NameError:
-    from sets import Set as set     # For Python 2.3
-
 phone_digits_re = re.compile(r'^(\d{2})[-\.]?(\d{4})[-\.]?(\d{4})$')
 
 class BRZipCodeField(RegexField):
diff --git a/django/contrib/messages/storage/fallback.py b/django/contrib/messages/storage/fallback.py
index 94e2decb79b..6c35343eb74 100644
--- a/django/contrib/messages/storage/fallback.py
+++ b/django/contrib/messages/storage/fallback.py
@@ -1,11 +1,6 @@
 from django.contrib.messages.storage.base import BaseStorage
 from django.contrib.messages.storage.cookie import CookieStorage
 from django.contrib.messages.storage.session import SessionStorage
-try:
-    set
-except NameError:
-    from sets import Set as set   # Python 2.3
-
 
 class FallbackStorage(BaseStorage):
     """
diff --git a/django/core/cache/backends/locmem.py b/django/core/cache/backends/locmem.py
index 5df891f9ad8..eff1201b977 100644
--- a/django/core/cache/backends/locmem.py
+++ b/django/core/cache/backends/locmem.py
@@ -77,7 +77,7 @@ class CacheClass(BaseCache):
 
     def set(self, key, value, timeout=None):
         self._lock.writer_enters()
-        # Python 2.3 and 2.4 don't allow combined try-except-finally blocks.
+        # Python 2.4 doesn't allow combined try-except-finally blocks.
         try:
             try:
                 self._set(key, pickle.dumps(value), timeout)
diff --git a/django/core/management/base.py b/django/core/management/base.py
index 0e1c9611050..4016faaa7a3 100644
--- a/django/core/management/base.py
+++ b/django/core/management/base.py
@@ -13,11 +13,6 @@ from django.core.exceptions import ImproperlyConfigured
 from django.core.management.color import color_style
 from django.utils.encoding import smart_str
 
-try:
-    set
-except NameError:
-    from sets import Set as set     # For Python 2.3
-
 class CommandError(Exception):
     """
     Exception class indicating a problem while executing a management
diff --git a/django/core/management/sql.py b/django/core/management/sql.py
index feb932f3300..695473dfa5d 100644
--- a/django/core/management/sql.py
+++ b/django/core/management/sql.py
@@ -9,11 +9,6 @@ from django.db import models
 from django.db.models import get_models
 from django.db.backends.util import truncate_name
 
-try:
-    set
-except NameError:
-    from sets import Set as set   # Python 2.3 fallback
-
 def sql_create(app, style, connection):
     "Returns a list of the CREATE TABLE SQL statements for the given app."
 
diff --git a/django/core/serializers/json.py b/django/core/serializers/json.py
index 27c7c30e5b1..b82c0a0ec71 100644
--- a/django/core/serializers/json.py
+++ b/django/core/serializers/json.py
@@ -3,6 +3,7 @@ Serialize data to/from JSON
 """
 
 import datetime
+import decimal
 from StringIO import StringIO
 
 from django.core.serializers.python import Serializer as PythonSerializer
@@ -10,11 +11,6 @@ from django.core.serializers.python import Deserializer as PythonDeserializer
 from django.utils import datetime_safe
 from django.utils import simplejson
 
-try:
-    import decimal
-except ImportError:
-    from django.utils import _decimal as decimal    # Python 2.3 fallback
-
 class Serializer(PythonSerializer):
     """
     Convert a queryset to JSON.
diff --git a/django/core/urlresolvers.py b/django/core/urlresolvers.py
index 3bb2c1c7cc1..cad57a5d9ff 100644
--- a/django/core/urlresolvers.py
+++ b/django/core/urlresolvers.py
@@ -19,12 +19,6 @@ from django.utils.importlib import import_module
 from django.utils.regex_helper import normalize
 from django.utils.thread_support import currentThread
 
-try:
-    reversed
-except NameError:
-    from django.utils.itercompat import reversed     # Python 2.3 fallback
-    from sets import Set as set
-
 _resolver_cache = {} # Maps URLconf modules to RegexURLResolver instances.
 _callable_cache = {} # Maps view and url pattern names to their view functions.
 
diff --git a/django/db/backends/creation.py b/django/db/backends/creation.py
index e3a9ce0272c..492ac1e3e93 100644
--- a/django/db/backends/creation.py
+++ b/django/db/backends/creation.py
@@ -1,10 +1,5 @@
 import sys
 import time
-try:
-    set
-except NameError:
-    # Python 2.3 compat
-    from sets import Set as set
 
 from django.conf import settings
 from django.core.management import call_command
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 711233a45ad..369e65baf74 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -9,10 +9,7 @@ import datetime
 import os
 import sys
 import time
-try:
-    from decimal import Decimal
-except ImportError:
-    from django.utils._decimal import Decimal
+from decimal import Decimal
 
 # Oracle takes client-side character set encoding from the environment.
 os.environ['NLS_LANG'] = '.UTF8'
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 1ed4a95e796..bc97f5cfd80 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -1,7 +1,7 @@
 """
 SQLite3 backend for django.
 
-Python 2.3 and 2.4 require pysqlite2 (http://pysqlite.org/).
+Python 2.4 requires pysqlite2 (http://pysqlite.org/).
 
 Python 2.5 and later can use a pysqlite2 module or the sqlite3 module in the
 standard library.
diff --git a/django/db/backends/util.py b/django/db/backends/util.py
index f9c07a9741f..7773273ba67 100644
--- a/django/db/backends/util.py
+++ b/django/db/backends/util.py
@@ -1,13 +1,9 @@
 import datetime
+import decimal
 from time import time
 
 from django.utils.hashcompat import md5_constructor
 
-try:
-    import decimal
-except ImportError:
-    from django.utils import _decimal as decimal    # for Python 2.3
-
 class CursorDebugWrapper(object):
     def __init__(self, cursor, db):
         self.cursor = cursor
diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index fe47ac8a0b2..65b60a01739 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -3,6 +3,7 @@ import decimal
 import re
 import time
 import math
+from itertools import tee
 
 import django.utils.copycompat as copy
 
@@ -14,7 +15,6 @@ from django import forms
 from django.core import exceptions, validators
 from django.utils.datastructures import DictWrapper
 from django.utils.functional import curry
-from django.utils.itercompat import tee
 from django.utils.text import capfirst
 from django.utils.translation import ugettext_lazy as _
 from django.utils.encoding import smart_unicode, force_unicode, smart_str
diff --git a/django/db/models/options.py b/django/db/models/options.py
index 250d5052671..5d84ab64720 100644
--- a/django/db/models/options.py
+++ b/django/db/models/options.py
@@ -1,9 +1,5 @@
 import re
 from bisect import bisect
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
 
 from django.conf import settings
 from django.db.models.related import RelatedObject
diff --git a/django/db/transaction.py b/django/db/transaction.py
index 31d717f4d27..3c767f1ae06 100644
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@@ -19,7 +19,7 @@ except ImportError:
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 from django.db import connections, DEFAULT_DB_ALIAS
 from django.conf import settings
 
diff --git a/django/dispatch/dispatcher.py b/django/dispatch/dispatcher.py
index e9198fc934c..de093346375 100644
--- a/django/dispatch/dispatcher.py
+++ b/django/dispatch/dispatcher.py
@@ -1,8 +1,4 @@
 import weakref
-try:
-    set
-except NameError:
-    from sets import Set as set # Python 2.3 fallback
 
 from django.dispatch import saferef
 
diff --git a/django/forms/models.py b/django/forms/models.py
index a0ef2de67f2..8accd61f30b 100644
--- a/django/forms/models.py
+++ b/django/forms/models.py
@@ -18,11 +18,6 @@ from widgets import SelectMultiple, HiddenInput, MultipleHiddenInput
 from widgets import media_property
 from formsets import BaseFormSet, formset_factory, DELETION_FIELD_NAME
 
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
-
 __all__ = (
     'ModelForm', 'BaseModelForm', 'model_to_dict', 'fields_for_model',
     'save_instance', 'form_for_fields', 'ModelChoiceField',
diff --git a/django/template/defaultfilters.py b/django/template/defaultfilters.py
index bea5938e5b8..4b720093b32 100644
--- a/django/template/defaultfilters.py
+++ b/django/template/defaultfilters.py
@@ -1,17 +1,12 @@
 """Default variable filters."""
 
 import re
-
-try:
-    from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
-except ImportError:
-    from django.utils._decimal import Decimal, InvalidOperation, ROUND_HALF_UP
-
+from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
 import random as random_module
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from django.template import Variable, Library
 from django.conf import settings
diff --git a/django/template/defaulttags.py b/django/template/defaulttags.py
index 96efa32c0f9..318ae5ffd2e 100644
--- a/django/template/defaulttags.py
+++ b/django/template/defaulttags.py
@@ -2,7 +2,7 @@
 
 import sys
 import re
-from itertools import cycle as itertools_cycle
+from itertools import groupby, cycle as itertools_cycle
 
 from django.template import Node, NodeList, Template, Context, Variable
 from django.template import TemplateSyntaxError, VariableDoesNotExist, BLOCK_TAG_START, BLOCK_TAG_END, VARIABLE_TAG_START, VARIABLE_TAG_END, SINGLE_BRACE_START, SINGLE_BRACE_END, COMMENT_TAG_START, COMMENT_TAG_END
@@ -10,7 +10,6 @@ from django.template import get_library, Library, InvalidTemplateLibrary
 from django.template.smartif import IfParser, Literal
 from django.conf import settings
 from django.utils.encoding import smart_str, smart_unicode
-from django.utils.itercompat import groupby
 from django.utils.safestring import mark_safe
 
 register = Library()
diff --git a/django/test/simple.py b/django/test/simple.py
index 0fc154fed1f..9013042e669 100644
--- a/django/test/simple.py
+++ b/django/test/simple.py
@@ -185,14 +185,6 @@ def build_test(label):
     # Construct a suite out of the tests that matched.
     return unittest.TestSuite(tests)
 
-# Python 2.3 compatibility: TestSuites were made iterable in 2.4.
-# We need to iterate over them, so we add the missing method when
-# necessary.
-try:
-    getattr(unittest.TestSuite, '__iter__')
-except AttributeError:
-    setattr(unittest.TestSuite, '__iter__', lambda s: iter(s._tests))
-
 def partition_suite(suite, classes, bins):
     """
     Partitions a test suite by test type.
diff --git a/django/utils/_decimal.py b/django/utils/_decimal.py
deleted file mode 100644
index 2801046cf17..00000000000
--- a/django/utils/_decimal.py
+++ /dev/null
@@ -1,3079 +0,0 @@
-# Copyright (c) 2004 Python Software Foundation.
-# All rights reserved.
-
-# Written by Eric Price <eprice at tjhsst.edu>
-#    and Facundo Batista <facundo at taniquetil.com.ar>
-#    and Raymond Hettinger <python at rcn.com>
-#    and Aahz <aahz at pobox.com>
-#    and Tim Peters
-
-# This module is currently Py2.3 compatible and should be kept that way
-# unless a major compelling advantage arises.  IOW, 2.3 compatibility is
-# strongly preferred, but not guaranteed.
-
-# Also, this module should be kept in sync with the latest updates of
-# the IBM specification as it evolves.  Those updates will be treated
-# as bug fixes (deviation from the spec is a compatibility, usability
-# bug) and will be backported.  At this point the spec is stabilizing
-# and the updates are becoming fewer, smaller, and less significant.
-
-"""
-This is a Py2.3 implementation of decimal floating point arithmetic based on
-the General Decimal Arithmetic Specification:
-
-    www2.hursley.ibm.com/decimal/decarith.html
-
-and IEEE standard 854-1987:
-
-    www.cs.berkeley.edu/~ejr/projects/754/private/drafts/854-1987/dir.html
-
-Decimal floating point has finite precision with arbitrarily large bounds.
-
-The purpose of the module is to support arithmetic using familiar
-"schoolhouse" rules and to avoid the some of tricky representation
-issues associated with binary floating point.  The package is especially
-useful for financial applications or for contexts where users have
-expectations that are at odds with binary floating point (for instance,
-in binary floating point, 1.00 % 0.1 gives 0.09999999999999995 instead
-of the expected Decimal("0.00") returned by decimal floating point).
-
-Here are some examples of using the decimal module:
-
->>> from decimal import *
->>> setcontext(ExtendedContext)
->>> Decimal(0)
-Decimal("0")
->>> Decimal("1")
-Decimal("1")
->>> Decimal("-.0123")
-Decimal("-0.0123")
->>> Decimal(123456)
-Decimal("123456")
->>> Decimal("123.45e12345678901234567890")
-Decimal("1.2345E+12345678901234567892")
->>> Decimal("1.33") + Decimal("1.27")
-Decimal("2.60")
->>> Decimal("12.34") + Decimal("3.87") - Decimal("18.41")
-Decimal("-2.20")
->>> dig = Decimal(1)
->>> print dig / Decimal(3)
-0.333333333
->>> getcontext().prec = 18
->>> print dig / Decimal(3)
-0.333333333333333333
->>> print dig.sqrt()
-1
->>> print Decimal(3).sqrt()
-1.73205080756887729
->>> print Decimal(3) ** 123
-4.85192780976896427E+58
->>> inf = Decimal(1) / Decimal(0)
->>> print inf
-Infinity
->>> neginf = Decimal(-1) / Decimal(0)
->>> print neginf
--Infinity
->>> print neginf + inf
-NaN
->>> print neginf * inf
--Infinity
->>> print dig / 0
-Infinity
->>> getcontext().traps[DivisionByZero] = 1
->>> print dig / 0
-Traceback (most recent call last):
-  ...
-  ...
-  ...
-DivisionByZero: x / 0
->>> c = Context()
->>> c.traps[InvalidOperation] = 0
->>> print c.flags[InvalidOperation]
-0
->>> c.divide(Decimal(0), Decimal(0))
-Decimal("NaN")
->>> c.traps[InvalidOperation] = 1
->>> print c.flags[InvalidOperation]
-1
->>> c.flags[InvalidOperation] = 0
->>> print c.flags[InvalidOperation]
-0
->>> print c.divide(Decimal(0), Decimal(0))
-Traceback (most recent call last):
-  ...
-  ...
-  ...
-InvalidOperation: 0 / 0
->>> print c.flags[InvalidOperation]
-1
->>> c.flags[InvalidOperation] = 0
->>> c.traps[InvalidOperation] = 0
->>> print c.divide(Decimal(0), Decimal(0))
-NaN
->>> print c.flags[InvalidOperation]
-1
->>>
-"""
-
-__all__ = [
-    # Two major classes
-    'Decimal', 'Context',
-
-    # Contexts
-    'DefaultContext', 'BasicContext', 'ExtendedContext',
-
-    # Exceptions
-    'DecimalException', 'Clamped', 'InvalidOperation', 'DivisionByZero',
-    'Inexact', 'Rounded', 'Subnormal', 'Overflow', 'Underflow',
-
-    # Constants for use in setting up contexts
-    'ROUND_DOWN', 'ROUND_HALF_UP', 'ROUND_HALF_EVEN', 'ROUND_CEILING',
-    'ROUND_FLOOR', 'ROUND_UP', 'ROUND_HALF_DOWN',
-
-    # Functions for manipulating contexts
-    'setcontext', 'getcontext'
-]
-
-import django.utils.copycompat as _copy
-
-#Rounding
-ROUND_DOWN = 'ROUND_DOWN'
-ROUND_HALF_UP = 'ROUND_HALF_UP'
-ROUND_HALF_EVEN = 'ROUND_HALF_EVEN'
-ROUND_CEILING = 'ROUND_CEILING'
-ROUND_FLOOR = 'ROUND_FLOOR'
-ROUND_UP = 'ROUND_UP'
-ROUND_HALF_DOWN = 'ROUND_HALF_DOWN'
-
-#Rounding decision (not part of the public API)
-NEVER_ROUND = 'NEVER_ROUND'    # Round in division (non-divmod), sqrt ONLY
-ALWAYS_ROUND = 'ALWAYS_ROUND'  # Every operation rounds at end.
-
-#Errors
-
-class DecimalException(ArithmeticError):
-    """Base exception class.
-
-    Used exceptions derive from this.
-    If an exception derives from another exception besides this (such as
-    Underflow (Inexact, Rounded, Subnormal) that indicates that it is only
-    called if the others are present.  This isn't actually used for
-    anything, though.
-
-    handle  -- Called when context._raise_error is called and the
-               trap_enabler is set.  First argument is self, second is the
-               context.  More arguments can be given, those being after
-               the explanation in _raise_error (For example,
-               context._raise_error(NewError, '(-x)!', self._sign) would
-               call NewError().handle(context, self._sign).)
-
-    To define a new exception, it should be sufficient to have it derive
-    from DecimalException.
-    """
-    def handle(self, context, *args):
-        pass
-
-
-class Clamped(DecimalException):
-    """Exponent of a 0 changed to fit bounds.
-
-    This occurs and signals clamped if the exponent of a result has been
-    altered in order to fit the constraints of a specific concrete
-    representation. This may occur when the exponent of a zero result would
-    be outside the bounds of a representation, or  when a large normal
-    number would have an encoded exponent that cannot be represented. In
-    this latter case, the exponent is reduced to fit and the corresponding
-    number of zero digits are appended to the coefficient ("fold-down").
-    """
-
-
-class InvalidOperation(DecimalException):
-    """An invalid operation was performed.
-
-    Various bad things cause this:
-
-    Something creates a signaling NaN
-    -INF + INF
-     0 * (+-)INF
-     (+-)INF / (+-)INF
-    x % 0
-    (+-)INF % x
-    x._rescale( non-integer )
-    sqrt(-x) , x > 0
-    0 ** 0
-    x ** (non-integer)
-    x ** (+-)INF
-    An operand is invalid
-    """
-    def handle(self, context, *args):
-        if args:
-            if args[0] == 1: #sNaN, must drop 's' but keep diagnostics
-                return Decimal( (args[1]._sign, args[1]._int, 'n') )
-        return NaN
-
-class ConversionSyntax(InvalidOperation):
-    """Trying to convert badly formed string.
-
-    This occurs and signals invalid-operation if an string is being
-    converted to a number and it does not conform to the numeric string
-    syntax. The result is [0,qNaN].
-    """
-
-    def handle(self, context, *args):
-        return (0, (0,), 'n') #Passed to something which uses a tuple.
-
-class DivisionByZero(DecimalException, ZeroDivisionError):
-    """Division by 0.
-
-    This occurs and signals division-by-zero if division of a finite number
-    by zero was attempted (during a divide-integer or divide operation, or a
-    power operation with negative right-hand operand), and the dividend was
-    not zero.
-
-    The result of the operation is [sign,inf], where sign is the exclusive
-    or of the signs of the operands for divide, or is 1 for an odd power of
-    -0, for power.
-    """
-
-    def handle(self, context, sign, double = None, *args):
-        if double is not None:
-            return (Infsign[sign],)*2
-        return Infsign[sign]
-
-class DivisionImpossible(InvalidOperation):
-    """Cannot perform the division adequately.
-
-    This occurs and signals invalid-operation if the integer result of a
-    divide-integer or remainder operation had too many digits (would be
-    longer than precision). The result is [0,qNaN].
-    """
-
-    def handle(self, context, *args):
-        return (NaN, NaN)
-
-class DivisionUndefined(InvalidOperation, ZeroDivisionError):
-    """Undefined result of division.
-
-    This occurs and signals invalid-operation if division by zero was
-    attempted (during a divide-integer, divide, or remainder operation), and
-    the dividend is also zero. The result is [0,qNaN].
-    """
-
-    def handle(self, context, tup=None, *args):
-        if tup is not None:
-            return (NaN, NaN) #for 0 %0, 0 // 0
-        return NaN
-
-class Inexact(DecimalException):
-    """Had to round, losing information.
-
-    This occurs and signals inexact whenever the result of an operation is
-    not exact (that is, it needed to be rounded and any discarded digits
-    were non-zero), or if an overflow or underflow condition occurs. The
-    result in all cases is unchanged.
-
-    The inexact signal may be tested (or trapped) to determine if a given
-    operation (or sequence of operations) was inexact.
-    """
-    pass
-
-class InvalidContext(InvalidOperation):
-    """Invalid context.  Unknown rounding, for example.
-
-    This occurs and signals invalid-operation if an invalid context was
-    detected during an operation. This can occur if contexts are not checked
-    on creation and either the precision exceeds the capability of the
-    underlying concrete representation or an unknown or unsupported rounding
-    was specified. These aspects of the context need only be checked when
-    the values are required to be used. The result is [0,qNaN].
-    """
-
-    def handle(self, context, *args):
-        return NaN
-
-class Rounded(DecimalException):
-    """Number got rounded (not  necessarily changed during rounding).
-
-    This occurs and signals rounded whenever the result of an operation is
-    rounded (that is, some zero or non-zero digits were discarded from the
-    coefficient), or if an overflow or underflow condition occurs. The
-    result in all cases is unchanged.
-
-    The rounded signal may be tested (or trapped) to determine if a given
-    operation (or sequence of operations) caused a loss of precision.
-    """
-    pass
-
-class Subnormal(DecimalException):
-    """Exponent < Emin before rounding.
-
-    This occurs and signals subnormal whenever the result of a conversion or
-    operation is subnormal (that is, its adjusted exponent is less than
-    Emin, before any rounding). The result in all cases is unchanged.
-
-    The subnormal signal may be tested (or trapped) to determine if a given
-    or operation (or sequence of operations) yielded a subnormal result.
-    """
-    pass
-
-class Overflow(Inexact, Rounded):
-    """Numerical overflow.
-
-    This occurs and signals overflow if the adjusted exponent of a result
-    (from a conversion or from an operation that is not an attempt to divide
-    by zero), after rounding, would be greater than the largest value that
-    can be handled by the implementation (the value Emax).
-
-    The result depends on the rounding mode:
-
-    For round-half-up and round-half-even (and for round-half-down and
-    round-up, if implemented), the result of the operation is [sign,inf],
-    where sign is the sign of the intermediate result. For round-down, the
-    result is the largest finite number that can be represented in the
-    current precision, with the sign of the intermediate result. For
-    round-ceiling, the result is the same as for round-down if the sign of
-    the intermediate result is 1, or is [0,inf] otherwise. For round-floor,
-    the result is the same as for round-down if the sign of the intermediate
-    result is 0, or is [1,inf] otherwise. In all cases, Inexact and Rounded
-    will also be raised.
-   """
-
-    def handle(self, context, sign, *args):
-        if context.rounding in (ROUND_HALF_UP, ROUND_HALF_EVEN,
-                                     ROUND_HALF_DOWN, ROUND_UP):
-            return Infsign[sign]
-        if sign == 0:
-            if context.rounding == ROUND_CEILING:
-                return Infsign[sign]
-            return Decimal((sign, (9,)*context.prec,
-                            context.Emax-context.prec+1))
-        if sign == 1:
-            if context.rounding == ROUND_FLOOR:
-                return Infsign[sign]
-            return Decimal( (sign, (9,)*context.prec,
-                             context.Emax-context.prec+1))
-
-
-class Underflow(Inexact, Rounded, Subnormal):
-    """Numerical underflow with result rounded to 0.
-
-    This occurs and signals underflow if a result is inexact and the
-    adjusted exponent of the result would be smaller (more negative) than
-    the smallest value that can be handled by the implementation (the value
-    Emin). That is, the result is both inexact and subnormal.
-
-    The result after an underflow will be a subnormal number rounded, if
-    necessary, so that its exponent is not less than Etiny. This may result
-    in 0 with the sign of the intermediate result and an exponent of Etiny.
-
-    In all cases, Inexact, Rounded, and Subnormal will also be raised.
-    """
-
-# List of public traps and flags
-_signals = [Clamped, DivisionByZero, Inexact, Overflow, Rounded,
-           Underflow, InvalidOperation, Subnormal]
-
-# Map conditions (per the spec) to signals
-_condition_map = {ConversionSyntax:InvalidOperation,
-                  DivisionImpossible:InvalidOperation,
-                  DivisionUndefined:InvalidOperation,
-                  InvalidContext:InvalidOperation}
-
-##### Context Functions #######################################
-
-# The getcontext() and setcontext() function manage access to a thread-local
-# current context.  Py2.4 offers direct support for thread locals.  If that
-# is not available, use threading.currentThread() which is slower but will
-# work for older Pythons.  If threads are not part of the build, create a
-# mock threading object with threading.local() returning the module namespace.
-
-try:
-    import threading
-except ImportError:
-    # Python was compiled without threads; create a mock object instead
-    import sys
-    class MockThreading:
-        def local(self, sys=sys):
-            return sys.modules[__name__]
-    threading = MockThreading()
-    del sys, MockThreading
-
-try:
-    threading.local
-
-except AttributeError:
-
-    #To fix reloading, force it to create a new context
-    #Old contexts have different exceptions in their dicts, making problems.
-    if hasattr(threading.currentThread(), '__decimal_context__'):
-        del threading.currentThread().__decimal_context__
-
-    def setcontext(context):
-        """Set this thread's context to context."""
-        if context in (DefaultContext, BasicContext, ExtendedContext):
-            context = context.copy()
-            context.clear_flags()
-        threading.currentThread().__decimal_context__ = context
-
-    def getcontext():
-        """Returns this thread's context.
-
-        If this thread does not yet have a context, returns
-        a new context and sets this thread's context.
-        New contexts are copies of DefaultContext.
-        """
-        try:
-            return threading.currentThread().__decimal_context__
-        except AttributeError:
-            context = Context()
-            threading.currentThread().__decimal_context__ = context
-            return context
-
-else:
-
-    local = threading.local()
-    if hasattr(local, '__decimal_context__'):
-        del local.__decimal_context__
-
-    def getcontext(_local=local):
-        """Returns this thread's context.
-
-        If this thread does not yet have a context, returns
-        a new context and sets this thread's context.
-        New contexts are copies of DefaultContext.
-        """
-        try:
-            return _local.__decimal_context__
-        except AttributeError:
-            context = Context()
-            _local.__decimal_context__ = context
-            return context
-
-    def setcontext(context, _local=local):
-        """Set this thread's context to context."""
-        if context in (DefaultContext, BasicContext, ExtendedContext):
-            context = context.copy()
-            context.clear_flags()
-        _local.__decimal_context__ = context
-
-    del threading, local        # Don't contaminate the namespace
-
-
-##### Decimal class ###########################################
-
-class Decimal(object):
-    """Floating point class for decimal arithmetic."""
-
-    __slots__ = ('_exp','_int','_sign', '_is_special')
-    # Generally, the value of the Decimal instance is given by
-    #  (-1)**_sign * _int * 10**_exp
-    # Special values are signified by _is_special == True
-
-    # We're immutable, so use __new__ not __init__
-    def __new__(cls, value="0", context=None):
-        """Create a decimal point instance.
-
-        >>> Decimal('3.14')              # string input
-        Decimal("3.14")
-        >>> Decimal((0, (3, 1, 4), -2))  # tuple input (sign, digit_tuple, exponent)
-        Decimal("3.14")
-        >>> Decimal(314)                 # int or long
-        Decimal("314")
-        >>> Decimal(Decimal(314))        # another decimal instance
-        Decimal("314")
-        """
-
-        self = object.__new__(cls)
-        self._is_special = False
-
-        # From an internal working value
-        if isinstance(value, _WorkRep):
-            self._sign = value.sign
-            self._int = tuple(map(int, str(value.int)))
-            self._exp = int(value.exp)
-            return self
-
-        # From another decimal
-        if isinstance(value, Decimal):
-            self._exp  = value._exp
-            self._sign = value._sign
-            self._int  = value._int
-            self._is_special  = value._is_special
-            return self
-
-        # From an integer
-        if isinstance(value, (int,long)):
-            if value >= 0:
-                self._sign = 0
-            else:
-                self._sign = 1
-            self._exp = 0
-            self._int = tuple(map(int, str(abs(value))))
-            return self
-
-        # tuple/list conversion (possibly from as_tuple())
-        if isinstance(value, (list,tuple)):
-            if len(value) != 3:
-                raise ValueError, 'Invalid arguments'
-            if value[0] not in (0,1):
-                raise ValueError, 'Invalid sign'
-            for digit in value[1]:
-                if not isinstance(digit, (int,long)) or digit < 0:
-                    raise ValueError, "The second value in the tuple must be composed of non negative integer elements."
-
-            self._sign = value[0]
-            self._int  = tuple(value[1])
-            if value[2] in ('F','n','N'):
-                self._exp = value[2]
-                self._is_special = True
-            else:
-                self._exp  = int(value[2])
-            return self
-
-        if isinstance(value, float):
-            raise TypeError("Cannot convert float to Decimal.  " +
-                            "First convert the float to a string")
-
-        # Other argument types may require the context during interpretation
-        if context is None:
-            context = getcontext()
-
-        # From a string
-        # REs insist on real strings, so we can too.
-        if isinstance(value, basestring):
-            if _isinfinity(value):
-                self._exp = 'F'
-                self._int = (0,)
-                self._is_special = True
-                if _isinfinity(value) == 1:
-                    self._sign = 0
-                else:
-                    self._sign = 1
-                return self
-            if _isnan(value):
-                sig, sign, diag = _isnan(value)
-                self._is_special = True
-                if len(diag) > context.prec: #Diagnostic info too long
-                    self._sign, self._int, self._exp = \
-                                context._raise_error(ConversionSyntax)
-                    return self
-                if sig == 1:
-                    self._exp = 'n' #qNaN
-                else: #sig == 2
-                    self._exp = 'N' #sNaN
-                self._sign = sign
-                self._int = tuple(map(int, diag)) #Diagnostic info
-                return self
-            try:
-                self._sign, self._int, self._exp = _string2exact(value)
-            except ValueError:
-                self._is_special = True
-                self._sign, self._int, self._exp = context._raise_error(ConversionSyntax)
-            return self
-
-        raise TypeError("Cannot convert %r to Decimal" % value)
-
-    def _isnan(self):
-        """Returns whether the number is not actually one.
-
-        0 if a number
-        1 if NaN
-        2 if sNaN
-        """
-        if self._is_special:
-            exp = self._exp
-            if exp == 'n':
-                return 1
-            elif exp == 'N':
-                return 2
-        return 0
-
-    def _isinfinity(self):
-        """Returns whether the number is infinite
-
-        0 if finite or not a number
-        1 if +INF
-        -1 if -INF
-        """
-        if self._exp == 'F':
-            if self._sign:
-                return -1
-            return 1
-        return 0
-
-    def _check_nans(self, other = None, context=None):
-        """Returns whether the number is not actually one.
-
-        if self, other are sNaN, signal
-        if self, other are NaN return nan
-        return 0
-
-        Done before operations.
-        """
-
-        self_is_nan = self._isnan()
-        if other is None:
-            other_is_nan = False
-        else:
-            other_is_nan = other._isnan()
-
-        if self_is_nan or other_is_nan:
-            if context is None:
-                context = getcontext()
-
-            if self_is_nan == 2:
-                return context._raise_error(InvalidOperation, 'sNaN',
-                                        1, self)
-            if other_is_nan == 2:
-                return context._raise_error(InvalidOperation, 'sNaN',
-                                        1, other)
-            if self_is_nan:
-                return self
-
-            return other
-        return 0
-
-    def __nonzero__(self):
-        """Is the number non-zero?
-
-        0 if self == 0
-        1 if self != 0
-        """
-        if self._is_special:
-            return 1
-        return sum(self._int) != 0
-
-    def __cmp__(self, other, context=None):
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                return 1 # Comparison involving NaN's always reports self > other
-
-            # INF = INF
-            return cmp(self._isinfinity(), other._isinfinity())
-
-        if not self and not other:
-            return 0 #If both 0, sign comparison isn't certain.
-
-        #If different signs, neg one is less
-        if other._sign < self._sign:
-            return -1
-        if self._sign < other._sign:
-            return 1
-
-        self_adjusted = self.adjusted()
-        other_adjusted = other.adjusted()
-        if self_adjusted == other_adjusted and \
-           self._int + (0,)*(self._exp - other._exp) == \
-           other._int + (0,)*(other._exp - self._exp):
-            return 0 #equal, except in precision. ([0]*(-x) = [])
-        elif self_adjusted > other_adjusted and self._int[0] != 0:
-            return (-1)**self._sign
-        elif self_adjusted < other_adjusted and other._int[0] != 0:
-            return -((-1)**self._sign)
-
-        # Need to round, so make sure we have a valid context
-        if context is None:
-            context = getcontext()
-
-        context = context._shallow_copy()
-        rounding = context._set_rounding(ROUND_UP) #round away from 0
-
-        flags = context._ignore_all_flags()
-        res = self.__sub__(other, context=context)
-
-        context._regard_flags(*flags)
-
-        context.rounding = rounding
-
-        if not res:
-            return 0
-        elif res._sign:
-            return -1
-        return 1
-
-    def __eq__(self, other):
-        if not isinstance(other, (Decimal, int, long)):
-            return NotImplemented
-        return self.__cmp__(other) == 0
-
-    def __ne__(self, other):
-        if not isinstance(other, (Decimal, int, long)):
-            return NotImplemented
-        return self.__cmp__(other) != 0
-
-    def compare(self, other, context=None):
-        """Compares one to another.
-
-        -1 => a < b
-        0  => a = b
-        1  => a > b
-        NaN => one is NaN
-        Like __cmp__, but returns Decimal instances.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        #compare(NaN, NaN) = NaN
-        if (self._is_special or other and other._is_special):
-            ans = self._check_nans(other, context)
-            if ans:
-                return ans
-
-        return Decimal(self.__cmp__(other, context))
-
-    def __hash__(self):
-        """x.__hash__() <==> hash(x)"""
-        # Decimal integers must hash the same as the ints
-        # Non-integer decimals are normalized and hashed as strings
-        # Normalization assures that hast(100E-1) == hash(10)
-        if self._is_special:
-            if self._isnan():
-                raise TypeError('Cannot hash a NaN value.')
-            return hash(str(self))
-        i = int(self)
-        if self == Decimal(i):
-            return hash(i)
-        assert self.__nonzero__()   # '-0' handled by integer case
-        return hash(str(self.normalize()))
-
-    def as_tuple(self):
-        """Represents the number as a triple tuple.
-
-        To show the internals exactly as they are.
-        """
-        return (self._sign, self._int, self._exp)
-
-    def __repr__(self):
-        """Represents the number as an instance of Decimal."""
-        # Invariant:  eval(repr(d)) == d
-        return 'Decimal("%s")' % str(self)
-
-    def __str__(self, eng = 0, context=None):
-        """Return string representation of the number in scientific notation.
-
-        Captures all of the information in the underlying representation.
-        """
-
-        if self._is_special:
-            if self._isnan():
-                minus = '-'*self._sign
-                if self._int == (0,):
-                    info = ''
-                else:
-                    info = ''.join(map(str, self._int))
-                if self._isnan() == 2:
-                    return minus + 'sNaN' + info
-                return minus + 'NaN' + info
-            if self._isinfinity():
-                minus = '-'*self._sign
-                return minus + 'Infinity'
-
-        if context is None:
-            context = getcontext()
-
-        tmp = map(str, self._int)
-        numdigits = len(self._int)
-        leftdigits = self._exp + numdigits
-        if eng and not self: #self = 0eX wants 0[.0[0]]eY, not [[0]0]0eY
-            if self._exp < 0 and self._exp >= -6: #short, no need for e/E
-                s = '-'*self._sign + '0.' + '0'*(abs(self._exp))
-                return s
-            #exp is closest mult. of 3 >= self._exp
-            exp = ((self._exp - 1)// 3 + 1) * 3
-            if exp != self._exp:
-                s = '0.'+'0'*(exp - self._exp)
-            else:
-                s = '0'
-            if exp != 0:
-                if context.capitals:
-                    s += 'E'
-                else:
-                    s += 'e'
-                if exp > 0:
-                    s += '+' #0.0e+3, not 0.0e3
-                s += str(exp)
-            s = '-'*self._sign + s
-            return s
-        if eng:
-            dotplace = (leftdigits-1)%3+1
-            adjexp = leftdigits -1 - (leftdigits-1)%3
-        else:
-            adjexp = leftdigits-1
-            dotplace = 1
-        if self._exp == 0:
-            pass
-        elif self._exp < 0 and adjexp >= 0:
-            tmp.insert(leftdigits, '.')
-        elif self._exp < 0 and adjexp >= -6:
-            tmp[0:0] = ['0'] * int(-leftdigits)
-            tmp.insert(0, '0.')
-        else:
-            if numdigits > dotplace:
-                tmp.insert(dotplace, '.')
-            elif numdigits < dotplace:
-                tmp.extend(['0']*(dotplace-numdigits))
-            if adjexp:
-                if not context.capitals:
-                    tmp.append('e')
-                else:
-                    tmp.append('E')
-                    if adjexp > 0:
-                        tmp.append('+')
-                tmp.append(str(adjexp))
-        if eng:
-            while tmp[0:1] == ['0']:
-                tmp[0:1] = []
-            if len(tmp) == 0 or tmp[0] == '.' or tmp[0].lower() == 'e':
-                tmp[0:0] = ['0']
-        if self._sign:
-            tmp.insert(0, '-')
-
-        return ''.join(tmp)
-
-    def to_eng_string(self, context=None):
-        """Convert to engineering-type string.
-
-        Engineering notation has an exponent which is a multiple of 3, so there
-        are up to 3 digits left of the decimal place.
-
-        Same rules for when in exponential and when as a value as in __str__.
-        """
-        return self.__str__(eng=1, context=context)
-
-    def __neg__(self, context=None):
-        """Returns a copy with the sign switched.
-
-        Rounds, if it has reason.
-        """
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-        if not self:
-            # -Decimal('0') is Decimal('0'), not Decimal('-0')
-            sign = 0
-        elif self._sign:
-            sign = 0
-        else:
-            sign = 1
-
-        if context is None:
-            context = getcontext()
-        if context._rounding_decision == ALWAYS_ROUND:
-            return Decimal((sign, self._int, self._exp))._fix(context)
-        return Decimal( (sign, self._int, self._exp))
-
-    def __pos__(self, context=None):
-        """Returns a copy, unless it is a sNaN.
-
-        Rounds the number (if more then precision digits)
-        """
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-        sign = self._sign
-        if not self:
-            # + (-0) = 0
-            sign = 0
-
-        if context is None:
-            context = getcontext()
-
-        if context._rounding_decision == ALWAYS_ROUND:
-            ans = self._fix(context)
-        else:
-            ans = Decimal(self)
-        ans._sign = sign
-        return ans
-
-    def __abs__(self, round=1, context=None):
-        """Returns the absolute value of self.
-
-        If the second argument is 0, do not round.
-        """
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-        if not round:
-            if context is None:
-                context = getcontext()
-            context = context._shallow_copy()
-            context._set_rounding_decision(NEVER_ROUND)
-
-        if self._sign:
-            ans = self.__neg__(context=context)
-        else:
-            ans = self.__pos__(context=context)
-
-        return ans
-
-    def __add__(self, other, context=None):
-        """Returns self + other.
-
-        -INF + INF (or the reverse) cause InvalidOperation errors.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if context is None:
-            context = getcontext()
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                return ans
-
-            if self._isinfinity():
-                #If both INF, same sign => same as both, opposite => error.
-                if self._sign != other._sign and other._isinfinity():
-                    return context._raise_error(InvalidOperation, '-INF + INF')
-                return Decimal(self)
-            if other._isinfinity():
-                return Decimal(other)  #Can't both be infinity here
-
-        shouldround = context._rounding_decision == ALWAYS_ROUND
-
-        exp = min(self._exp, other._exp)
-        negativezero = 0
-        if context.rounding == ROUND_FLOOR and self._sign != other._sign:
-            #If the answer is 0, the sign should be negative, in this case.
-            negativezero = 1
-
-        if not self and not other:
-            sign = min(self._sign, other._sign)
-            if negativezero:
-                sign = 1
-            return Decimal( (sign, (0,), exp))
-        if not self:
-            exp = max(exp, other._exp - context.prec-1)
-            ans = other._rescale(exp, watchexp=0, context=context)
-            if shouldround:
-                ans = ans._fix(context)
-            return ans
-        if not other:
-            exp = max(exp, self._exp - context.prec-1)
-            ans = self._rescale(exp, watchexp=0, context=context)
-            if shouldround:
-                ans = ans._fix(context)
-            return ans
-
-        op1 = _WorkRep(self)
-        op2 = _WorkRep(other)
-        op1, op2 = _normalize(op1, op2, shouldround, context.prec)
-
-        result = _WorkRep()
-        if op1.sign != op2.sign:
-            # Equal and opposite
-            if op1.int == op2.int:
-                if exp < context.Etiny():
-                    exp = context.Etiny()
-                    context._raise_error(Clamped)
-                return Decimal((negativezero, (0,), exp))
-            if op1.int < op2.int:
-                op1, op2 = op2, op1
-                #OK, now abs(op1) > abs(op2)
-            if op1.sign == 1:
-                result.sign = 1
-                op1.sign, op2.sign = op2.sign, op1.sign
-            else:
-                result.sign = 0
-                #So we know the sign, and op1 > 0.
-        elif op1.sign == 1:
-            result.sign = 1
-            op1.sign, op2.sign = (0, 0)
-        else:
-            result.sign = 0
-        #Now, op1 > abs(op2) > 0
-
-        if op2.sign == 0:
-            result.int = op1.int + op2.int
-        else:
-            result.int = op1.int - op2.int
-
-        result.exp = op1.exp
-        ans = Decimal(result)
-        if shouldround:
-            ans = ans._fix(context)
-        return ans
-
-    __radd__ = __add__
-
-    def __sub__(self, other, context=None):
-        """Return self + (-other)"""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context=context)
-            if ans:
-                return ans
-
-        # -Decimal(0) = Decimal(0), which we don't want since
-        # (-0 - 0 = -0 + (-0) = -0, but -0 + 0 = 0.)
-        # so we change the sign directly to a copy
-        tmp = Decimal(other)
-        tmp._sign = 1-tmp._sign
-
-        return self.__add__(tmp, context=context)
-
-    def __rsub__(self, other, context=None):
-        """Return other + (-self)"""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        tmp = Decimal(self)
-        tmp._sign = 1 - tmp._sign
-        return other.__add__(tmp, context=context)
-
-    def _increment(self, round=1, context=None):
-        """Special case of add, adding 1eExponent
-
-        Since it is common, (rounding, for example) this adds
-        (sign)*one E self._exp to the number more efficiently than add.
-
-        For example:
-        Decimal('5.624e10')._increment() == Decimal('5.625e10')
-        """
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-            return Decimal(self) # Must be infinite, and incrementing makes no difference
-
-        L = list(self._int)
-        L[-1] += 1
-        spot = len(L)-1
-        while L[spot] == 10:
-            L[spot] = 0
-            if spot == 0:
-                L[0:0] = [1]
-                break
-            L[spot-1] += 1
-            spot -= 1
-        ans = Decimal((self._sign, L, self._exp))
-
-        if context is None:
-            context = getcontext()
-        if round and context._rounding_decision == ALWAYS_ROUND:
-            ans = ans._fix(context)
-        return ans
-
-    def __mul__(self, other, context=None):
-        """Return self * other.
-
-        (+-) INF * 0 (or its reverse) raise InvalidOperation.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if context is None:
-            context = getcontext()
-
-        resultsign = self._sign ^ other._sign
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                return ans
-
-            if self._isinfinity():
-                if not other:
-                    return context._raise_error(InvalidOperation, '(+-)INF * 0')
-                return Infsign[resultsign]
-
-            if other._isinfinity():
-                if not self:
-                    return context._raise_error(InvalidOperation, '0 * (+-)INF')
-                return Infsign[resultsign]
-
-        resultexp = self._exp + other._exp
-        shouldround = context._rounding_decision == ALWAYS_ROUND
-
-        # Special case for multiplying by zero
-        if not self or not other:
-            ans = Decimal((resultsign, (0,), resultexp))
-            if shouldround:
-                #Fixing in case the exponent is out of bounds
-                ans = ans._fix(context)
-            return ans
-
-        # Special case for multiplying by power of 10
-        if self._int == (1,):
-            ans = Decimal((resultsign, other._int, resultexp))
-            if shouldround:
-                ans = ans._fix(context)
-            return ans
-        if other._int == (1,):
-            ans = Decimal((resultsign, self._int, resultexp))
-            if shouldround:
-                ans = ans._fix(context)
-            return ans
-
-        op1 = _WorkRep(self)
-        op2 = _WorkRep(other)
-
-        ans = Decimal( (resultsign, map(int, str(op1.int * op2.int)), resultexp))
-        if shouldround:
-            ans = ans._fix(context)
-
-        return ans
-    __rmul__ = __mul__
-
-    def __div__(self, other, context=None):
-        """Return self / other."""
-        return self._divide(other, context=context)
-    __truediv__ = __div__
-
-    def _divide(self, other, divmod = 0, context=None):
-        """Return a / b, to context.prec precision.
-
-        divmod:
-        0 => true division
-        1 => (a //b, a%b)
-        2 => a //b
-        3 => a%b
-
-        Actually, if divmod is 2 or 3 a tuple is returned, but errors for
-        computing the other value are not raised.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            if divmod in (0, 1):
-                return NotImplemented
-            return (NotImplemented, NotImplemented)
-
-        if context is None:
-            context = getcontext()
-
-        sign = self._sign ^ other._sign
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                if divmod:
-                    return (ans, ans)
-                return ans
-
-            if self._isinfinity() and other._isinfinity():
-                if divmod:
-                    return (context._raise_error(InvalidOperation,
-                                            '(+-)INF // (+-)INF'),
-                            context._raise_error(InvalidOperation,
-                                            '(+-)INF % (+-)INF'))
-                return context._raise_error(InvalidOperation, '(+-)INF/(+-)INF')
-
-            if self._isinfinity():
-                if divmod == 1:
-                    return (Infsign[sign],
-                            context._raise_error(InvalidOperation, 'INF % x'))
-                elif divmod == 2:
-                    return (Infsign[sign], NaN)
-                elif divmod == 3:
-                    return (Infsign[sign],
-                            context._raise_error(InvalidOperation, 'INF % x'))
-                return Infsign[sign]
-
-            if other._isinfinity():
-                if divmod:
-                    return (Decimal((sign, (0,), 0)), Decimal(self))
-                context._raise_error(Clamped, 'Division by infinity')
-                return Decimal((sign, (0,), context.Etiny()))
-
-        # Special cases for zeroes
-        if not self and not other:
-            if divmod:
-                return context._raise_error(DivisionUndefined, '0 / 0', 1)
-            return context._raise_error(DivisionUndefined, '0 / 0')
-
-        if not self:
-            if divmod:
-                otherside = Decimal(self)
-                otherside._exp = min(self._exp, other._exp)
-                return (Decimal((sign, (0,), 0)),  otherside)
-            exp = self._exp - other._exp
-            if exp < context.Etiny():
-                exp = context.Etiny()
-                context._raise_error(Clamped, '0e-x / y')
-            if exp > context.Emax:
-                exp = context.Emax
-                context._raise_error(Clamped, '0e+x / y')
-            return Decimal( (sign, (0,), exp) )
-
-        if not other:
-            if divmod:
-                return context._raise_error(DivisionByZero, 'divmod(x,0)',
-                                           sign, 1)
-            return context._raise_error(DivisionByZero, 'x / 0', sign)
-
-        #OK, so neither = 0, INF or NaN
-
-        shouldround = context._rounding_decision == ALWAYS_ROUND
-
-        #If we're dividing into ints, and self < other, stop.
-        #self.__abs__(0) does not round.
-        if divmod and (self.__abs__(0, context) < other.__abs__(0, context)):
-
-            if divmod == 1 or divmod == 3:
-                exp = min(self._exp, other._exp)
-                ans2 = self._rescale(exp, context=context, watchexp=0)
-                if shouldround:
-                    ans2 = ans2._fix(context)
-                return (Decimal( (sign, (0,), 0) ),
-                        ans2)
-
-            elif divmod == 2:
-                #Don't round the mod part, if we don't need it.
-                return (Decimal( (sign, (0,), 0) ), Decimal(self))
-
-        op1 = _WorkRep(self)
-        op2 = _WorkRep(other)
-        op1, op2, adjust = _adjust_coefficients(op1, op2)
-        res = _WorkRep( (sign, 0, (op1.exp - op2.exp)) )
-        if divmod and res.exp > context.prec + 1:
-            return context._raise_error(DivisionImpossible)
-
-        prec_limit = 10 ** context.prec
-        while 1:
-            while op2.int <= op1.int:
-                res.int += 1
-                op1.int -= op2.int
-            if res.exp == 0 and divmod:
-                if res.int >= prec_limit and shouldround:
-                    return context._raise_error(DivisionImpossible)
-                otherside = Decimal(op1)
-                frozen = context._ignore_all_flags()
-
-                exp = min(self._exp, other._exp)
-                otherside = otherside._rescale(exp, context=context, watchexp=0)
-                context._regard_flags(*frozen)
-                if shouldround:
-                    otherside = otherside._fix(context)
-                return (Decimal(res), otherside)
-
-            if op1.int == 0 and adjust >= 0 and not divmod:
-                break
-            if res.int >= prec_limit and shouldround:
-                if divmod:
-                    return context._raise_error(DivisionImpossible)
-                shouldround=1
-                # Really, the answer is a bit higher, so adding a one to
-                # the end will make sure the rounding is right.
-                if op1.int != 0:
-                    res.int *= 10
-                    res.int += 1
-                    res.exp -= 1
-
-                break
-            res.int *= 10
-            res.exp -= 1
-            adjust += 1
-            op1.int *= 10
-            op1.exp -= 1
-
-            if res.exp == 0 and divmod and op2.int > op1.int:
-                #Solves an error in precision.  Same as a previous block.
-
-                if res.int >= prec_limit and shouldround:
-                    return context._raise_error(DivisionImpossible)
-                otherside = Decimal(op1)
-                frozen = context._ignore_all_flags()
-
-                exp = min(self._exp, other._exp)
-                otherside = otherside._rescale(exp, context=context)
-
-                context._regard_flags(*frozen)
-
-                return (Decimal(res), otherside)
-
-        ans = Decimal(res)
-        if shouldround:
-            ans = ans._fix(context)
-        return ans
-
-    def __rdiv__(self, other, context=None):
-        """Swaps self/other and returns __div__."""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-        return other.__div__(self, context=context)
-    __rtruediv__ = __rdiv__
-
-    def __divmod__(self, other, context=None):
-        """
-        (self // other, self % other)
-        """
-        return self._divide(other, 1, context)
-
-    def __rdivmod__(self, other, context=None):
-        """Swaps self/other and returns __divmod__."""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-        return other.__divmod__(self, context=context)
-
-    def __mod__(self, other, context=None):
-        """
-        self % other
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                return ans
-
-        if self and not other:
-            return context._raise_error(InvalidOperation, 'x % 0')
-
-        return self._divide(other, 3, context)[1]
-
-    def __rmod__(self, other, context=None):
-        """Swaps self/other and returns __mod__."""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-        return other.__mod__(self, context=context)
-
-    def remainder_near(self, other, context=None):
-        """
-        Remainder nearest to 0-  abs(remainder-near) <= other/2
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            ans = self._check_nans(other, context)
-            if ans:
-                return ans
-        if self and not other:
-            return context._raise_error(InvalidOperation, 'x % 0')
-
-        if context is None:
-            context = getcontext()
-        # If DivisionImpossible causes an error, do not leave Rounded/Inexact
-        # ignored in the calling function.
-        context = context._shallow_copy()
-        flags = context._ignore_flags(Rounded, Inexact)
-        #keep DivisionImpossible flags
-        (side, r) = self.__divmod__(other, context=context)
-
-        if r._isnan():
-            context._regard_flags(*flags)
-            return r
-
-        context = context._shallow_copy()
-        rounding = context._set_rounding_decision(NEVER_ROUND)
-
-        if other._sign:
-            comparison = other.__div__(Decimal(-2), context=context)
-        else:
-            comparison = other.__div__(Decimal(2), context=context)
-
-        context._set_rounding_decision(rounding)
-        context._regard_flags(*flags)
-
-        s1, s2 = r._sign, comparison._sign
-        r._sign, comparison._sign = 0, 0
-
-        if r < comparison:
-            r._sign, comparison._sign = s1, s2
-            #Get flags now
-            self.__divmod__(other, context=context)
-            return r._fix(context)
-        r._sign, comparison._sign = s1, s2
-
-        rounding = context._set_rounding_decision(NEVER_ROUND)
-
-        (side, r) = self.__divmod__(other, context=context)
-        context._set_rounding_decision(rounding)
-        if r._isnan():
-            return r
-
-        decrease = not side._iseven()
-        rounding = context._set_rounding_decision(NEVER_ROUND)
-        side = side.__abs__(context=context)
-        context._set_rounding_decision(rounding)
-
-        s1, s2 = r._sign, comparison._sign
-        r._sign, comparison._sign = 0, 0
-        if r > comparison or decrease and r == comparison:
-            r._sign, comparison._sign = s1, s2
-            context.prec += 1
-            if len(side.__add__(Decimal(1), context=context)._int) >= context.prec:
-                context.prec -= 1
-                return context._raise_error(DivisionImpossible)[1]
-            context.prec -= 1
-            if self._sign == other._sign:
-                r = r.__sub__(other, context=context)
-            else:
-                r = r.__add__(other, context=context)
-        else:
-            r._sign, comparison._sign = s1, s2
-
-        return r._fix(context)
-
-    def __floordiv__(self, other, context=None):
-        """self // other"""
-        return self._divide(other, 2, context)[0]
-
-    def __rfloordiv__(self, other, context=None):
-        """Swaps self/other and returns __floordiv__."""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-        return other.__floordiv__(self, context=context)
-
-    def __float__(self):
-        """Float representation."""
-        return float(str(self))
-
-    def __int__(self):
-        """Converts self to an int, truncating if necessary."""
-        if self._is_special:
-            if self._isnan():
-                context = getcontext()
-                return context._raise_error(InvalidContext)
-            elif self._isinfinity():
-                raise OverflowError, "Cannot convert infinity to long"
-        if self._exp >= 0:
-            s = ''.join(map(str, self._int)) + '0'*self._exp
-        else:
-            s = ''.join(map(str, self._int))[:self._exp]
-        if s == '':
-            s = '0'
-        sign = '-'*self._sign
-        return int(sign + s)
-
-    def __long__(self):
-        """Converts to a long.
-
-        Equivalent to long(int(self))
-        """
-        return long(self.__int__())
-
-    def _fix(self, context):
-        """Round if it is necessary to keep self within prec precision.
-
-        Rounds and fixes the exponent.  Does not raise on a sNaN.
-
-        Arguments:
-        self - Decimal instance
-        context - context used.
-        """
-        if self._is_special:
-            return self
-        if context is None:
-            context = getcontext()
-        prec = context.prec
-        ans = self._fixexponents(context)
-        if len(ans._int) > prec:
-            ans = ans._round(prec, context=context)
-            ans = ans._fixexponents(context)
-        return ans
-
-    def _fixexponents(self, context):
-        """Fix the exponents and return a copy with the exponent in bounds.
-        Only call if known to not be a special value.
-        """
-        folddown = context._clamp
-        Emin = context.Emin
-        ans = self
-        ans_adjusted = ans.adjusted()
-        if ans_adjusted < Emin:
-            Etiny = context.Etiny()
-            if ans._exp < Etiny:
-                if not ans:
-                    ans = Decimal(self)
-                    ans._exp = Etiny
-                    context._raise_error(Clamped)
-                    return ans
-                ans = ans._rescale(Etiny, context=context)
-                #It isn't zero, and exp < Emin => subnormal
-                context._raise_error(Subnormal)
-                if context.flags[Inexact]:
-                    context._raise_error(Underflow)
-            else:
-                if ans:
-                    #Only raise subnormal if non-zero.
-                    context._raise_error(Subnormal)
-        else:
-            Etop = context.Etop()
-            if folddown and ans._exp > Etop:
-                context._raise_error(Clamped)
-                ans = ans._rescale(Etop, context=context)
-            else:
-                Emax = context.Emax
-                if ans_adjusted > Emax:
-                    if not ans:
-                        ans = Decimal(self)
-                        ans._exp = Emax
-                        context._raise_error(Clamped)
-                        return ans
-                    context._raise_error(Inexact)
-                    context._raise_error(Rounded)
-                    return context._raise_error(Overflow, 'above Emax', ans._sign)
-        return ans
-
-    def _round(self, prec=None, rounding=None, context=None):
-        """Returns a rounded version of self.
-
-        You can specify the precision or rounding method.  Otherwise, the
-        context determines it.
-        """
-
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-            if self._isinfinity():
-                return Decimal(self)
-
-        if context is None:
-            context = getcontext()
-
-        if rounding is None:
-            rounding = context.rounding
-        if prec is None:
-            prec = context.prec
-
-        if not self:
-            if prec <= 0:
-                dig = (0,)
-                exp = len(self._int) - prec + self._exp
-            else:
-                dig = (0,) * prec
-                exp = len(self._int) + self._exp - prec
-            ans = Decimal((self._sign, dig, exp))
-            context._raise_error(Rounded)
-            return ans
-
-        if prec == 0:
-            temp = Decimal(self)
-            temp._int = (0,)+temp._int
-            prec = 1
-        elif prec < 0:
-            exp = self._exp + len(self._int) - prec - 1
-            temp = Decimal( (self._sign, (0, 1), exp))
-            prec = 1
-        else:
-            temp = Decimal(self)
-
-        numdigits = len(temp._int)
-        if prec == numdigits:
-            return temp
-
-        # See if we need to extend precision
-        expdiff = prec - numdigits
-        if expdiff > 0:
-            tmp = list(temp._int)
-            tmp.extend([0] * expdiff)
-            ans =  Decimal( (temp._sign, tmp, temp._exp - expdiff))
-            return ans
-
-        #OK, but maybe all the lost digits are 0.
-        lostdigits = self._int[expdiff:]
-        if lostdigits == (0,) * len(lostdigits):
-            ans = Decimal( (temp._sign, temp._int[:prec], temp._exp - expdiff))
-            #Rounded, but not Inexact
-            context._raise_error(Rounded)
-            return ans
-
-        # Okay, let's round and lose data
-
-        this_function = getattr(temp, self._pick_rounding_function[rounding])
-        #Now we've got the rounding function
-
-        if prec != context.prec:
-            context = context._shallow_copy()
-            context.prec = prec
-        ans = this_function(prec, expdiff, context)
-        context._raise_error(Rounded)
-        context._raise_error(Inexact, 'Changed in rounding')
-
-        return ans
-
-    _pick_rounding_function = {}
-
-    def _round_down(self, prec, expdiff, context):
-        """Also known as round-towards-0, truncate."""
-        return Decimal( (self._sign, self._int[:prec], self._exp - expdiff) )
-
-    def _round_half_up(self, prec, expdiff, context, tmp = None):
-        """Rounds 5 up (away from 0)"""
-
-        if tmp is None:
-            tmp = Decimal( (self._sign,self._int[:prec], self._exp - expdiff))
-        if self._int[prec] >= 5:
-            tmp = tmp._increment(round=0, context=context)
-            if len(tmp._int) > prec:
-                return Decimal( (tmp._sign, tmp._int[:-1], tmp._exp + 1))
-        return tmp
-
-    def _round_half_even(self, prec, expdiff, context):
-        """Round 5 to even, rest to nearest."""
-
-        tmp = Decimal( (self._sign, self._int[:prec], self._exp - expdiff))
-        half = (self._int[prec] == 5)
-        if half:
-            for digit in self._int[prec+1:]:
-                if digit != 0:
-                    half = 0
-                    break
-        if half:
-            if self._int[prec-1] & 1 == 0:
-                return tmp
-        return self._round_half_up(prec, expdiff, context, tmp)
-
-    def _round_half_down(self, prec, expdiff, context):
-        """Round 5 down"""
-
-        tmp = Decimal( (self._sign, self._int[:prec], self._exp - expdiff))
-        half = (self._int[prec] == 5)
-        if half:
-            for digit in self._int[prec+1:]:
-                if digit != 0:
-                    half = 0
-                    break
-        if half:
-            return tmp
-        return self._round_half_up(prec, expdiff, context, tmp)
-
-    def _round_up(self, prec, expdiff, context):
-        """Rounds away from 0."""
-        tmp = Decimal( (self._sign, self._int[:prec], self._exp - expdiff) )
-        for digit in self._int[prec:]:
-            if digit != 0:
-                tmp = tmp._increment(round=1, context=context)
-                if len(tmp._int) > prec:
-                    return Decimal( (tmp._sign, tmp._int[:-1], tmp._exp + 1))
-                else:
-                    return tmp
-        return tmp
-
-    def _round_ceiling(self, prec, expdiff, context):
-        """Rounds up (not away from 0 if negative.)"""
-        if self._sign:
-            return self._round_down(prec, expdiff, context)
-        else:
-            return self._round_up(prec, expdiff, context)
-
-    def _round_floor(self, prec, expdiff, context):
-        """Rounds down (not towards 0 if negative)"""
-        if not self._sign:
-            return self._round_down(prec, expdiff, context)
-        else:
-            return self._round_up(prec, expdiff, context)
-
-    def __pow__(self, n, modulo = None, context=None):
-        """Return self ** n (mod modulo)
-
-        If modulo is None (default), don't take it mod modulo.
-        """
-        n = _convert_other(n)
-        if n is NotImplemented:
-            return n
-
-        if context is None:
-            context = getcontext()
-
-        if self._is_special or n._is_special or n.adjusted() > 8:
-            #Because the spot << doesn't work with really big exponents
-            if n._isinfinity() or n.adjusted() > 8:
-                return context._raise_error(InvalidOperation, 'x ** INF')
-
-            ans = self._check_nans(n, context)
-            if ans:
-                return ans
-
-        if not n._isinteger():
-            return context._raise_error(InvalidOperation, 'x ** (non-integer)')
-
-        if not self and not n:
-            return context._raise_error(InvalidOperation, '0 ** 0')
-
-        if not n:
-            return Decimal(1)
-
-        if self == Decimal(1):
-            return Decimal(1)
-
-        sign = self._sign and not n._iseven()
-        n = int(n)
-
-        if self._isinfinity():
-            if modulo:
-                return context._raise_error(InvalidOperation, 'INF % x')
-            if n > 0:
-                return Infsign[sign]
-            return Decimal( (sign, (0,), 0) )
-
-        #with ludicrously large exponent, just raise an overflow and return inf.
-        if not modulo and n > 0 and (self._exp + len(self._int) - 1) * n > context.Emax \
-           and self:
-
-            tmp = Decimal('inf')
-            tmp._sign = sign
-            context._raise_error(Rounded)
-            context._raise_error(Inexact)
-            context._raise_error(Overflow, 'Big power', sign)
-            return tmp
-
-        elength = len(str(abs(n)))
-        firstprec = context.prec
-
-        if not modulo and firstprec + elength + 1 > DefaultContext.Emax:
-            return context._raise_error(Overflow, 'Too much precision.', sign)
-
-        mul = Decimal(self)
-        val = Decimal(1)
-        context = context._shallow_copy()
-        context.prec = firstprec + elength + 1
-        if n < 0:
-            #n is a long now, not Decimal instance
-            n = -n
-            mul = Decimal(1).__div__(mul, context=context)
-
-        spot = 1
-        while spot <= n:
-            spot <<= 1
-
-        spot >>= 1
-        #Spot is the highest power of 2 less than n
-        while spot:
-            val = val.__mul__(val, context=context)
-            if val._isinfinity():
-                val = Infsign[sign]
-                break
-            if spot & n:
-                val = val.__mul__(mul, context=context)
-            if modulo is not None:
-                val = val.__mod__(modulo, context=context)
-            spot >>= 1
-        context.prec = firstprec
-
-        if context._rounding_decision == ALWAYS_ROUND:
-            return val._fix(context)
-        return val
-
-    def __rpow__(self, other, context=None):
-        """Swaps self/other and returns __pow__."""
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-        return other.__pow__(self, context=context)
-
-    def normalize(self, context=None):
-        """Normalize- strip trailing 0s, change anything equal to 0 to 0e0"""
-
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-        dup = self._fix(context)
-        if dup._isinfinity():
-            return dup
-
-        if not dup:
-            return Decimal( (dup._sign, (0,), 0) )
-        end = len(dup._int)
-        exp = dup._exp
-        while dup._int[end-1] == 0:
-            exp += 1
-            end -= 1
-        return Decimal( (dup._sign, dup._int[:end], exp) )
-
-
-    def quantize(self, exp, rounding=None, context=None, watchexp=1):
-        """Quantize self so its exponent is the same as that of exp.
-
-        Similar to self._rescale(exp._exp) but with error checking.
-        """
-        if self._is_special or exp._is_special:
-            ans = self._check_nans(exp, context)
-            if ans:
-                return ans
-
-            if exp._isinfinity() or self._isinfinity():
-                if exp._isinfinity() and self._isinfinity():
-                    return self  #if both are inf, it is OK
-                if context is None:
-                    context = getcontext()
-                return context._raise_error(InvalidOperation,
-                                        'quantize with one INF')
-        return self._rescale(exp._exp, rounding, context, watchexp)
-
-    def same_quantum(self, other):
-        """Test whether self and other have the same exponent.
-
-        same as self._exp == other._exp, except NaN == sNaN
-        """
-        if self._is_special or other._is_special:
-            if self._isnan() or other._isnan():
-                return self._isnan() and other._isnan() and True
-            if self._isinfinity() or other._isinfinity():
-                return self._isinfinity() and other._isinfinity() and True
-        return self._exp == other._exp
-
-    def _rescale(self, exp, rounding=None, context=None, watchexp=1):
-        """Rescales so that the exponent is exp.
-
-        exp = exp to scale to (an integer)
-        rounding = rounding version
-        watchexp: if set (default) an error is returned if exp is greater
-        than Emax or less than Etiny.
-        """
-        if context is None:
-            context = getcontext()
-
-        if self._is_special:
-            if self._isinfinity():
-                return context._raise_error(InvalidOperation, 'rescale with an INF')
-
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-        if watchexp and (context.Emax  < exp or context.Etiny() > exp):
-            return context._raise_error(InvalidOperation, 'rescale(a, INF)')
-
-        if not self:
-            ans = Decimal(self)
-            ans._int = (0,)
-            ans._exp = exp
-            return ans
-
-        diff = self._exp - exp
-        digits = len(self._int) + diff
-
-        if watchexp and digits > context.prec:
-            return context._raise_error(InvalidOperation, 'Rescale > prec')
-
-        tmp = Decimal(self)
-        tmp._int = (0,) + tmp._int
-        digits += 1
-
-        if digits < 0:
-            tmp._exp = -digits + tmp._exp
-            tmp._int = (0,1)
-            digits = 1
-        tmp = tmp._round(digits, rounding, context=context)
-
-        if tmp._int[0] == 0 and len(tmp._int) > 1:
-            tmp._int = tmp._int[1:]
-        tmp._exp = exp
-
-        tmp_adjusted = tmp.adjusted()
-        if tmp and tmp_adjusted < context.Emin:
-            context._raise_error(Subnormal)
-        elif tmp and tmp_adjusted > context.Emax:
-            return context._raise_error(InvalidOperation, 'rescale(a, INF)')
-        return tmp
-
-    def to_integral(self, rounding=None, context=None):
-        """Rounds to the nearest integer, without raising inexact, rounded."""
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-        if self._exp >= 0:
-            return self
-        if context is None:
-            context = getcontext()
-        flags = context._ignore_flags(Rounded, Inexact)
-        ans = self._rescale(0, rounding, context=context)
-        context._regard_flags(flags)
-        return ans
-
-    def sqrt(self, context=None):
-        """Return the square root of self.
-
-        Uses a converging algorithm (Xn+1 = 0.5*(Xn + self / Xn))
-        Should quadratically approach the right answer.
-        """
-        if self._is_special:
-            ans = self._check_nans(context=context)
-            if ans:
-                return ans
-
-            if self._isinfinity() and self._sign == 0:
-                return Decimal(self)
-
-        if not self:
-            #exponent = self._exp / 2, using round_down.
-            #if self._exp < 0:
-            #    exp = (self._exp+1) // 2
-            #else:
-            exp = (self._exp) // 2
-            if self._sign == 1:
-                #sqrt(-0) = -0
-                return Decimal( (1, (0,), exp))
-            else:
-                return Decimal( (0, (0,), exp))
-
-        if context is None:
-            context = getcontext()
-
-        if self._sign == 1:
-            return context._raise_error(InvalidOperation, 'sqrt(-x), x > 0')
-
-        tmp = Decimal(self)
-
-        expadd = tmp._exp // 2
-        if tmp._exp & 1:
-            tmp._int += (0,)
-            tmp._exp = 0
-        else:
-            tmp._exp = 0
-
-        context = context._shallow_copy()
-        flags = context._ignore_all_flags()
-        firstprec = context.prec
-        context.prec = 3
-        if tmp.adjusted() & 1 == 0:
-            ans = Decimal( (0, (8,1,9), tmp.adjusted()  - 2) )
-            ans = ans.__add__(tmp.__mul__(Decimal((0, (2,5,9), -2)),
-                                          context=context), context=context)
-            ans._exp -= 1 + tmp.adjusted() // 2
-        else:
-            ans = Decimal( (0, (2,5,9), tmp._exp + len(tmp._int)- 3) )
-            ans = ans.__add__(tmp.__mul__(Decimal((0, (8,1,9), -3)),
-                                          context=context), context=context)
-            ans._exp -= 1 + tmp.adjusted()  // 2
-
-        #ans is now a linear approximation.
-
-        Emax, Emin = context.Emax, context.Emin
-        context.Emax, context.Emin = DefaultContext.Emax, DefaultContext.Emin
-
-        half = Decimal('0.5')
-
-        maxp = firstprec + 2
-        rounding = context._set_rounding(ROUND_HALF_EVEN)
-        while 1:
-            context.prec = min(2*context.prec - 2, maxp)
-            ans = half.__mul__(ans.__add__(tmp.__div__(ans, context=context),
-                                           context=context), context=context)
-            if context.prec == maxp:
-                break
-
-        #round to the answer's precision-- the only error can be 1 ulp.
-        context.prec = firstprec
-        prevexp = ans.adjusted()
-        ans = ans._round(context=context)
-
-        #Now, check if the other last digits are better.
-        context.prec = firstprec + 1
-        # In case we rounded up another digit and we should actually go lower.
-        if prevexp != ans.adjusted():
-            ans._int += (0,)
-            ans._exp -= 1
-
-
-        lower = ans.__sub__(Decimal((0, (5,), ans._exp-1)), context=context)
-        context._set_rounding(ROUND_UP)
-        if lower.__mul__(lower, context=context) > (tmp):
-            ans = ans.__sub__(Decimal((0, (1,), ans._exp)), context=context)
-
-        else:
-            upper = ans.__add__(Decimal((0, (5,), ans._exp-1)),context=context)
-            context._set_rounding(ROUND_DOWN)
-            if upper.__mul__(upper, context=context) < tmp:
-                ans = ans.__add__(Decimal((0, (1,), ans._exp)),context=context)
-
-        ans._exp += expadd
-
-        context.prec = firstprec
-        context.rounding = rounding
-        ans = ans._fix(context)
-
-        rounding = context._set_rounding_decision(NEVER_ROUND)
-        if not ans.__mul__(ans, context=context) == self:
-            # Only rounded/inexact if here.
-            context._regard_flags(flags)
-            context._raise_error(Rounded)
-            context._raise_error(Inexact)
-        else:
-            #Exact answer, so let's set the exponent right.
-            #if self._exp < 0:
-            #    exp = (self._exp +1)// 2
-            #else:
-            exp = self._exp // 2
-            context.prec += ans._exp - exp
-            ans = ans._rescale(exp, context=context)
-            context.prec = firstprec
-            context._regard_flags(flags)
-        context.Emax, context.Emin = Emax, Emin
-
-        return ans._fix(context)
-
-    def max(self, other, context=None):
-        """Returns the larger value.
-
-        like max(self, other) except if one is not a number, returns
-        NaN (and signals if one is sNaN).  Also rounds.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            # if one operand is a quiet NaN and the other is number, then the
-            # number is always returned
-            sn = self._isnan()
-            on = other._isnan()
-            if sn or on:
-                if on == 1 and sn != 2:
-                    return self
-                if sn == 1 and on != 2:
-                    return other
-                return self._check_nans(other, context)
-
-        ans = self
-        c = self.__cmp__(other)
-        if c == 0:
-            # if both operands are finite and equal in numerical value
-            # then an ordering is applied:
-            #
-            # if the signs differ then max returns the operand with the
-            # positive sign and min returns the operand with the negative sign
-            #
-            # if the signs are the same then the exponent is used to select
-            # the result.
-            if self._sign != other._sign:
-                if self._sign:
-                    ans = other
-            elif self._exp < other._exp and not self._sign:
-                ans = other
-            elif self._exp > other._exp and self._sign:
-                ans = other
-        elif c == -1:
-            ans = other
-
-        if context is None:
-            context = getcontext()
-        if context._rounding_decision == ALWAYS_ROUND:
-            return ans._fix(context)
-        return ans
-
-    def min(self, other, context=None):
-        """Returns the smaller value.
-
-        like min(self, other) except if one is not a number, returns
-        NaN (and signals if one is sNaN).  Also rounds.
-        """
-        other = _convert_other(other)
-        if other is NotImplemented:
-            return other
-
-        if self._is_special or other._is_special:
-            # if one operand is a quiet NaN and the other is number, then the
-            # number is always returned
-            sn = self._isnan()
-            on = other._isnan()
-            if sn or on:
-                if on == 1 and sn != 2:
-                    return self
-                if sn == 1 and on != 2:
-                    return other
-                return self._check_nans(other, context)
-
-        ans = self
-        c = self.__cmp__(other)
-        if c == 0:
-            # if both operands are finite and equal in numerical value
-            # then an ordering is applied:
-            #
-            # if the signs differ then max returns the operand with the
-            # positive sign and min returns the operand with the negative sign
-            #
-            # if the signs are the same then the exponent is used to select
-            # the result.
-            if self._sign != other._sign:
-                if other._sign:
-                    ans = other
-            elif self._exp > other._exp and not self._sign:
-                ans = other
-            elif self._exp < other._exp and self._sign:
-                ans = other
-        elif c == 1:
-            ans = other
-
-        if context is None:
-            context = getcontext()
-        if context._rounding_decision == ALWAYS_ROUND:
-            return ans._fix(context)
-        return ans
-
-    def _isinteger(self):
-        """Returns whether self is an integer"""
-        if self._exp >= 0:
-            return True
-        rest = self._int[self._exp:]
-        return rest == (0,)*len(rest)
-
-    def _iseven(self):
-        """Returns 1 if self is even.  Assumes self is an integer."""
-        if self._exp > 0:
-            return 1
-        return self._int[-1+self._exp] & 1 == 0
-
-    def adjusted(self):
-        """Return the adjusted exponent of self"""
-        try:
-            return self._exp + len(self._int) - 1
-        #If NaN or Infinity, self._exp is string
-        except TypeError:
-            return 0
-
-    # support for pickling, copy, and deepcopy
-    def __reduce__(self):
-        return (self.__class__, (str(self),))
-
-    def __copy__(self):
-        if type(self) == Decimal:
-            return self     # I'm immutable; therefore I am my own clone
-        return self.__class__(str(self))
-
-    def __deepcopy__(self, memo):
-        if type(self) == Decimal:
-            return self     # My components are also immutable
-        return self.__class__(str(self))
-
-##### Context class ###########################################
-
-
-# get rounding method function:
-rounding_functions = [name for name in Decimal.__dict__.keys() if name.startswith('_round_')]
-for name in rounding_functions:
-    #name is like _round_half_even, goes to the global ROUND_HALF_EVEN value.
-    globalname = name[1:].upper()
-    val = globals()[globalname]
-    Decimal._pick_rounding_function[val] = name
-
-del name, val, globalname, rounding_functions
-
-class Context(object):
-    """Contains the context for a Decimal instance.
-
-    Contains:
-    prec - precision (for use in rounding, division, square roots..)
-    rounding - rounding type. (how you round)
-    _rounding_decision - ALWAYS_ROUND, NEVER_ROUND -- do you round?
-    traps - If traps[exception] = 1, then the exception is
-                    raised when it is caused.  Otherwise, a value is
-                    substituted in.
-    flags  - When an exception is caused, flags[exception] is incremented.
-             (Whether or not the trap_enabler is set)
-             Should be reset by user of Decimal instance.
-    Emin -   Minimum exponent
-    Emax -   Maximum exponent
-    capitals -      If 1, 1*10^1 is printed as 1E+1.
-                    If 0, printed as 1e1
-    _clamp - If 1, change exponents if too high (Default 0)
-    """
-
-    def __init__(self, prec=None, rounding=None,
-                 traps=None, flags=None,
-                 _rounding_decision=None,
-                 Emin=None, Emax=None,
-                 capitals=None, _clamp=0,
-                 _ignored_flags=None):
-        if flags is None:
-            flags = []
-        if _ignored_flags is None:
-            _ignored_flags = []
-        if not isinstance(flags, dict):
-            flags = dict([(s,s in flags) for s in _signals])
-            del s
-        if traps is not None and not isinstance(traps, dict):
-            traps = dict([(s,s in traps) for s in _signals])
-            del s
-        for name, val in locals().items():
-            if val is None:
-                setattr(self, name, _copy.copy(getattr(DefaultContext, name)))
-            else:
-                setattr(self, name, val)
-        del self.self
-
-    def __repr__(self):
-        """Show the current context."""
-        s = []
-        s.append('Context(prec=%(prec)d, rounding=%(rounding)s, Emin=%(Emin)d, Emax=%(Emax)d, capitals=%(capitals)d' % vars(self))
-        s.append('flags=[' + ', '.join([f.__name__ for f, v in self.flags.items() if v]) + ']')
-        s.append('traps=[' + ', '.join([t.__name__ for t, v in self.traps.items() if v]) + ']')
-        return ', '.join(s) + ')'
-
-    def clear_flags(self):
-        """Reset all flags to zero"""
-        for flag in self.flags:
-            self.flags[flag] = 0
-
-    def _shallow_copy(self):
-        """Returns a shallow copy from self."""
-        nc = Context(self.prec, self.rounding, self.traps, self.flags,
-                         self._rounding_decision, self.Emin, self.Emax,
-                         self.capitals, self._clamp, self._ignored_flags)
-        return nc
-
-    def copy(self):
-        """Returns a deep copy from self."""
-        nc = Context(self.prec, self.rounding, self.traps.copy(), self.flags.copy(),
-                         self._rounding_decision, self.Emin, self.Emax,
-                         self.capitals, self._clamp, self._ignored_flags)
-        return nc
-    __copy__ = copy
-
-    def _raise_error(self, condition, explanation = None, *args):
-        """Handles an error
-
-        If the flag is in _ignored_flags, returns the default response.
-        Otherwise, it increments the flag, then, if the corresponding
-        trap_enabler is set, it reaises the exception.  Otherwise, it returns
-        the default value after incrementing the flag.
-        """
-        error = _condition_map.get(condition, condition)
-        if error in self._ignored_flags:
-            #Don't touch the flag
-            return error().handle(self, *args)
-
-        self.flags[error] += 1
-        if not self.traps[error]:
-            #The errors define how to handle themselves.
-            return condition().handle(self, *args)
-
-        # Errors should only be risked on copies of the context
-        #self._ignored_flags = []
-        raise error, explanation
-
-    def _ignore_all_flags(self):
-        """Ignore all flags, if they are raised"""
-        return self._ignore_flags(*_signals)
-
-    def _ignore_flags(self, *flags):
-        """Ignore the flags, if they are raised"""
-        # Do not mutate-- This way, copies of a context leave the original
-        # alone.
-        self._ignored_flags = (self._ignored_flags + list(flags))
-        return list(flags)
-
-    def _regard_flags(self, *flags):
-        """Stop ignoring the flags, if they are raised"""
-        if flags and isinstance(flags[0], (tuple,list)):
-            flags = flags[0]
-        for flag in flags:
-            self._ignored_flags.remove(flag)
-
-    def __hash__(self):
-        """A Context cannot be hashed."""
-        # We inherit object.__hash__, so we must deny this explicitly
-        raise TypeError, "Cannot hash a Context."
-
-    def Etiny(self):
-        """Returns Etiny (= Emin - prec + 1)"""
-        return int(self.Emin - self.prec + 1)
-
-    def Etop(self):
-        """Returns maximum exponent (= Emax - prec + 1)"""
-        return int(self.Emax - self.prec + 1)
-
-    def _set_rounding_decision(self, type):
-        """Sets the rounding decision.
-
-        Sets the rounding decision, and returns the current (previous)
-        rounding decision.  Often used like:
-
-        context = context._shallow_copy()
-        # That so you don't change the calling context
-        # if an error occurs in the middle (say DivisionImpossible is raised).
-
-        rounding = context._set_rounding_decision(NEVER_ROUND)
-        instance = instance / Decimal(2)
-        context._set_rounding_decision(rounding)
-
-        This will make it not round for that operation.
-        """
-
-        rounding = self._rounding_decision
-        self._rounding_decision = type
-        return rounding
-
-    def _set_rounding(self, type):
-        """Sets the rounding type.
-
-        Sets the rounding type, and returns the current (previous)
-        rounding type.  Often used like:
-
-        context = context.copy()
-        # so you don't change the calling context
-        # if an error occurs in the middle.
-        rounding = context._set_rounding(ROUND_UP)
-        val = self.__sub__(other, context=context)
-        context._set_rounding(rounding)
-
-        This will make it round up for that operation.
-        """
-        rounding = self.rounding
-        self.rounding= type
-        return rounding
-
-    def create_decimal(self, num='0'):
-        """Creates a new Decimal instance but using self as context."""
-        d = Decimal(num, context=self)
-        return d._fix(self)
-
-    #Methods
-    def abs(self, a):
-        """Returns the absolute value of the operand.
-
-        If the operand is negative, the result is the same as using the minus
-        operation on the operand. Otherwise, the result is the same as using
-        the plus operation on the operand.
-
-        >>> ExtendedContext.abs(Decimal('2.1'))
-        Decimal("2.1")
-        >>> ExtendedContext.abs(Decimal('-100'))
-        Decimal("100")
-        >>> ExtendedContext.abs(Decimal('101.5'))
-        Decimal("101.5")
-        >>> ExtendedContext.abs(Decimal('-101.5'))
-        Decimal("101.5")
-        """
-        return a.__abs__(context=self)
-
-    def add(self, a, b):
-        """Return the sum of the two operands.
-
-        >>> ExtendedContext.add(Decimal('12'), Decimal('7.00'))
-        Decimal("19.00")
-        >>> ExtendedContext.add(Decimal('1E+2'), Decimal('1.01E+4'))
-        Decimal("1.02E+4")
-        """
-        return a.__add__(b, context=self)
-
-    def _apply(self, a):
-        return str(a._fix(self))
-
-    def compare(self, a, b):
-        """Compares values numerically.
-
-        If the signs of the operands differ, a value representing each operand
-        ('-1' if the operand is less than zero, '0' if the operand is zero or
-        negative zero, or '1' if the operand is greater than zero) is used in
-        place of that operand for the comparison instead of the actual
-        operand.
-
-        The comparison is then effected by subtracting the second operand from
-        the first and then returning a value according to the result of the
-        subtraction: '-1' if the result is less than zero, '0' if the result is
-        zero or negative zero, or '1' if the result is greater than zero.
-
-        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('3'))
-        Decimal("-1")
-        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.1'))
-        Decimal("0")
-        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.10'))
-        Decimal("0")
-        >>> ExtendedContext.compare(Decimal('3'), Decimal('2.1'))
-        Decimal("1")
-        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('-3'))
-        Decimal("1")
-        >>> ExtendedContext.compare(Decimal('-3'), Decimal('2.1'))
-        Decimal("-1")
-        """
-        return a.compare(b, context=self)
-
-    def divide(self, a, b):
-        """Decimal division in a specified context.
-
-        >>> ExtendedContext.divide(Decimal('1'), Decimal('3'))
-        Decimal("0.333333333")
-        >>> ExtendedContext.divide(Decimal('2'), Decimal('3'))
-        Decimal("0.666666667")
-        >>> ExtendedContext.divide(Decimal('5'), Decimal('2'))
-        Decimal("2.5")
-        >>> ExtendedContext.divide(Decimal('1'), Decimal('10'))
-        Decimal("0.1")
-        >>> ExtendedContext.divide(Decimal('12'), Decimal('12'))
-        Decimal("1")
-        >>> ExtendedContext.divide(Decimal('8.00'), Decimal('2'))
-        Decimal("4.00")
-        >>> ExtendedContext.divide(Decimal('2.400'), Decimal('2.0'))
-        Decimal("1.20")
-        >>> ExtendedContext.divide(Decimal('1000'), Decimal('100'))
-        Decimal("10")
-        >>> ExtendedContext.divide(Decimal('1000'), Decimal('1'))
-        Decimal("1000")
-        >>> ExtendedContext.divide(Decimal('2.40E+6'), Decimal('2'))
-        Decimal("1.20E+6")
-        """
-        return a.__div__(b, context=self)
-
-    def divide_int(self, a, b):
-        """Divides two numbers and returns the integer part of the result.
-
-        >>> ExtendedContext.divide_int(Decimal('2'), Decimal('3'))
-        Decimal("0")
-        >>> ExtendedContext.divide_int(Decimal('10'), Decimal('3'))
-        Decimal("3")
-        >>> ExtendedContext.divide_int(Decimal('1'), Decimal('0.3'))
-        Decimal("3")
-        """
-        return a.__floordiv__(b, context=self)
-
-    def divmod(self, a, b):
-        return a.__divmod__(b, context=self)
-
-    def max(self, a,b):
-        """max compares two values numerically and returns the maximum.
-
-        If either operand is a NaN then the general rules apply.
-        Otherwise, the operands are compared as as though by the compare
-        operation. If they are numerically equal then the left-hand operand
-        is chosen as the result. Otherwise the maximum (closer to positive
-        infinity) of the two operands is chosen as the result.
-
-        >>> ExtendedContext.max(Decimal('3'), Decimal('2'))
-        Decimal("3")
-        >>> ExtendedContext.max(Decimal('-10'), Decimal('3'))
-        Decimal("3")
-        >>> ExtendedContext.max(Decimal('1.0'), Decimal('1'))
-        Decimal("1")
-        >>> ExtendedContext.max(Decimal('7'), Decimal('NaN'))
-        Decimal("7")
-        """
-        return a.max(b, context=self)
-
-    def min(self, a,b):
-        """min compares two values numerically and returns the minimum.
-
-        If either operand is a NaN then the general rules apply.
-        Otherwise, the operands are compared as as though by the compare
-        operation. If they are numerically equal then the left-hand operand
-        is chosen as the result. Otherwise the minimum (closer to negative
-        infinity) of the two operands is chosen as the result.
-
-        >>> ExtendedContext.min(Decimal('3'), Decimal('2'))
-        Decimal("2")
-        >>> ExtendedContext.min(Decimal('-10'), Decimal('3'))
-        Decimal("-10")
-        >>> ExtendedContext.min(Decimal('1.0'), Decimal('1'))
-        Decimal("1.0")
-        >>> ExtendedContext.min(Decimal('7'), Decimal('NaN'))
-        Decimal("7")
-        """
-        return a.min(b, context=self)
-
-    def minus(self, a):
-        """Minus corresponds to unary prefix minus in Python.
-
-        The operation is evaluated using the same rules as subtract; the
-        operation minus(a) is calculated as subtract('0', a) where the '0'
-        has the same exponent as the operand.
-
-        >>> ExtendedContext.minus(Decimal('1.3'))
-        Decimal("-1.3")
-        >>> ExtendedContext.minus(Decimal('-1.3'))
-        Decimal("1.3")
-        """
-        return a.__neg__(context=self)
-
-    def multiply(self, a, b):
-        """multiply multiplies two operands.
-
-        If either operand is a special value then the general rules apply.
-        Otherwise, the operands are multiplied together ('long multiplication'),
-        resulting in a number which may be as long as the sum of the lengths
-        of the two operands.
-
-        >>> ExtendedContext.multiply(Decimal('1.20'), Decimal('3'))
-        Decimal("3.60")
-        >>> ExtendedContext.multiply(Decimal('7'), Decimal('3'))
-        Decimal("21")
-        >>> ExtendedContext.multiply(Decimal('0.9'), Decimal('0.8'))
-        Decimal("0.72")
-        >>> ExtendedContext.multiply(Decimal('0.9'), Decimal('-0'))
-        Decimal("-0.0")
-        >>> ExtendedContext.multiply(Decimal('654321'), Decimal('654321'))
-        Decimal("4.28135971E+11")
-        """
-        return a.__mul__(b, context=self)
-
-    def normalize(self, a):
-        """normalize reduces an operand to its simplest form.
-
-        Essentially a plus operation with all trailing zeros removed from the
-        result.
-
-        >>> ExtendedContext.normalize(Decimal('2.1'))
-        Decimal("2.1")
-        >>> ExtendedContext.normalize(Decimal('-2.0'))
-        Decimal("-2")
-        >>> ExtendedContext.normalize(Decimal('1.200'))
-        Decimal("1.2")
-        >>> ExtendedContext.normalize(Decimal('-120'))
-        Decimal("-1.2E+2")
-        >>> ExtendedContext.normalize(Decimal('120.00'))
-        Decimal("1.2E+2")
-        >>> ExtendedContext.normalize(Decimal('0.00'))
-        Decimal("0")
-        """
-        return a.normalize(context=self)
-
-    def plus(self, a):
-        """Plus corresponds to unary prefix plus in Python.
-
-        The operation is evaluated using the same rules as add; the
-        operation plus(a) is calculated as add('0', a) where the '0'
-        has the same exponent as the operand.
-
-        >>> ExtendedContext.plus(Decimal('1.3'))
-        Decimal("1.3")
-        >>> ExtendedContext.plus(Decimal('-1.3'))
-        Decimal("-1.3")
-        """
-        return a.__pos__(context=self)
-
-    def power(self, a, b, modulo=None):
-        """Raises a to the power of b, to modulo if given.
-
-        The right-hand operand must be a whole number whose integer part (after
-        any exponent has been applied) has no more than 9 digits and whose
-        fractional part (if any) is all zeros before any rounding. The operand
-        may be positive, negative, or zero; if negative, the absolute value of
-        the power is used, and the left-hand operand is inverted (divided into
-        1) before use.
-
-        If the increased precision needed for the intermediate calculations
-        exceeds the capabilities of the implementation then an Invalid operation
-        condition is raised.
-
-        If, when raising to a negative power, an underflow occurs during the
-        division into 1, the operation is not halted at that point but
-        continues.
-
-        >>> ExtendedContext.power(Decimal('2'), Decimal('3'))
-        Decimal("8")
-        >>> ExtendedContext.power(Decimal('2'), Decimal('-3'))
-        Decimal("0.125")
-        >>> ExtendedContext.power(Decimal('1.7'), Decimal('8'))
-        Decimal("69.7575744")
-        >>> ExtendedContext.power(Decimal('Infinity'), Decimal('-2'))
-        Decimal("0")
-        >>> ExtendedContext.power(Decimal('Infinity'), Decimal('-1'))
-        Decimal("0")
-        >>> ExtendedContext.power(Decimal('Infinity'), Decimal('0'))
-        Decimal("1")
-        >>> ExtendedContext.power(Decimal('Infinity'), Decimal('1'))
-        Decimal("Infinity")
-        >>> ExtendedContext.power(Decimal('Infinity'), Decimal('2'))
-        Decimal("Infinity")
-        >>> ExtendedContext.power(Decimal('-Infinity'), Decimal('-2'))
-        Decimal("0")
-        >>> ExtendedContext.power(Decimal('-Infinity'), Decimal('-1'))
-        Decimal("-0")
-        >>> ExtendedContext.power(Decimal('-Infinity'), Decimal('0'))
-        Decimal("1")
-        >>> ExtendedContext.power(Decimal('-Infinity'), Decimal('1'))
-        Decimal("-Infinity")
-        >>> ExtendedContext.power(Decimal('-Infinity'), Decimal('2'))
-        Decimal("Infinity")
-        >>> ExtendedContext.power(Decimal('0'), Decimal('0'))
-        Decimal("NaN")
-        """
-        return a.__pow__(b, modulo, context=self)
-
-    def quantize(self, a, b):
-        """Returns a value equal to 'a' (rounded) and having the exponent of 'b'.
-
-        The coefficient of the result is derived from that of the left-hand
-        operand. It may be rounded using the current rounding setting (if the
-        exponent is being increased), multiplied by a positive power of ten (if
-        the exponent is being decreased), or is unchanged (if the exponent is
-        already equal to that of the right-hand operand).
-
-        Unlike other operations, if the length of the coefficient after the
-        quantize operation would be greater than precision then an Invalid
-        operation condition is raised. This guarantees that, unless there is an
-        error condition, the exponent of the result of a quantize is always
-        equal to that of the right-hand operand.
-
-        Also unlike other operations, quantize will never raise Underflow, even
-        if the result is subnormal and inexact.
-
-        >>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.001'))
-        Decimal("2.170")
-        >>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.01'))
-        Decimal("2.17")
-        >>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.1'))
-        Decimal("2.2")
-        >>> ExtendedContext.quantize(Decimal('2.17'), Decimal('1e+0'))
-        Decimal("2")
-        >>> ExtendedContext.quantize(Decimal('2.17'), Decimal('1e+1'))
-        Decimal("0E+1")
-        >>> ExtendedContext.quantize(Decimal('-Inf'), Decimal('Infinity'))
-        Decimal("-Infinity")
-        >>> ExtendedContext.quantize(Decimal('2'), Decimal('Infinity'))
-        Decimal("NaN")
-        >>> ExtendedContext.quantize(Decimal('-0.1'), Decimal('1'))
-        Decimal("-0")
-        >>> ExtendedContext.quantize(Decimal('-0'), Decimal('1e+5'))
-        Decimal("-0E+5")
-        >>> ExtendedContext.quantize(Decimal('+35236450.6'), Decimal('1e-2'))
-        Decimal("NaN")
-        >>> ExtendedContext.quantize(Decimal('-35236450.6'), Decimal('1e-2'))
-        Decimal("NaN")
-        >>> ExtendedContext.quantize(Decimal('217'), Decimal('1e-1'))
-        Decimal("217.0")
-        >>> ExtendedContext.quantize(Decimal('217'), Decimal('1e-0'))
-        Decimal("217")
-        >>> ExtendedContext.quantize(Decimal('217'), Decimal('1e+1'))
-        Decimal("2.2E+2")
-        >>> ExtendedContext.quantize(Decimal('217'), Decimal('1e+2'))
-        Decimal("2E+2")
-        """
-        return a.quantize(b, context=self)
-
-    def remainder(self, a, b):
-        """Returns the remainder from integer division.
-
-        The result is the residue of the dividend after the operation of
-        calculating integer division as described for divide-integer, rounded to
-        precision digits if necessary. The sign of the result, if non-zero, is
-        the same as that of the original dividend.
-
-        This operation will fail under the same conditions as integer division
-        (that is, if integer division on the same two operands would fail, the
-        remainder cannot be calculated).
-
-        >>> ExtendedContext.remainder(Decimal('2.1'), Decimal('3'))
-        Decimal("2.1")
-        >>> ExtendedContext.remainder(Decimal('10'), Decimal('3'))
-        Decimal("1")
-        >>> ExtendedContext.remainder(Decimal('-10'), Decimal('3'))
-        Decimal("-1")
-        >>> ExtendedContext.remainder(Decimal('10.2'), Decimal('1'))
-        Decimal("0.2")
-        >>> ExtendedContext.remainder(Decimal('10'), Decimal('0.3'))
-        Decimal("0.1")
-        >>> ExtendedContext.remainder(Decimal('3.6'), Decimal('1.3'))
-        Decimal("1.0")
-        """
-        return a.__mod__(b, context=self)
-
-    def remainder_near(self, a, b):
-        """Returns to be "a - b * n", where n is the integer nearest the exact
-        value of "x / b" (if two integers are equally near then the even one
-        is chosen). If the result is equal to 0 then its sign will be the
-        sign of a.
-
-        This operation will fail under the same conditions as integer division
-        (that is, if integer division on the same two operands would fail, the
-        remainder cannot be calculated).
-
-        >>> ExtendedContext.remainder_near(Decimal('2.1'), Decimal('3'))
-        Decimal("-0.9")
-        >>> ExtendedContext.remainder_near(Decimal('10'), Decimal('6'))
-        Decimal("-2")
-        >>> ExtendedContext.remainder_near(Decimal('10'), Decimal('3'))
-        Decimal("1")
-        >>> ExtendedContext.remainder_near(Decimal('-10'), Decimal('3'))
-        Decimal("-1")
-        >>> ExtendedContext.remainder_near(Decimal('10.2'), Decimal('1'))
-        Decimal("0.2")
-        >>> ExtendedContext.remainder_near(Decimal('10'), Decimal('0.3'))
-        Decimal("0.1")
-        >>> ExtendedContext.remainder_near(Decimal('3.6'), Decimal('1.3'))
-        Decimal("-0.3")
-        """
-        return a.remainder_near(b, context=self)
-
-    def same_quantum(self, a, b):
-        """Returns True if the two operands have the same exponent.
-
-        The result is never affected by either the sign or the coefficient of
-        either operand.
-
-        >>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('0.001'))
-        False
-        >>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('0.01'))
-        True
-        >>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('1'))
-        False
-        >>> ExtendedContext.same_quantum(Decimal('Inf'), Decimal('-Inf'))
-        True
-        """
-        return a.same_quantum(b)
-
-    def sqrt(self, a):
-        """Returns the square root of a non-negative number to context precision.
-
-        If the result must be inexact, it is rounded using the round-half-even
-        algorithm.
-
-        >>> ExtendedContext.sqrt(Decimal('0'))
-        Decimal("0")
-        >>> ExtendedContext.sqrt(Decimal('-0'))
-        Decimal("-0")
-        >>> ExtendedContext.sqrt(Decimal('0.39'))
-        Decimal("0.624499800")
-        >>> ExtendedContext.sqrt(Decimal('100'))
-        Decimal("10")
-        >>> ExtendedContext.sqrt(Decimal('1'))
-        Decimal("1")
-        >>> ExtendedContext.sqrt(Decimal('1.0'))
-        Decimal("1.0")
-        >>> ExtendedContext.sqrt(Decimal('1.00'))
-        Decimal("1.0")
-        >>> ExtendedContext.sqrt(Decimal('7'))
-        Decimal("2.64575131")
-        >>> ExtendedContext.sqrt(Decimal('10'))
-        Decimal("3.16227766")
-        >>> ExtendedContext.prec
-        9
-        """
-        return a.sqrt(context=self)
-
-    def subtract(self, a, b):
-        """Return the difference between the two operands.
-
-        >>> ExtendedContext.subtract(Decimal('1.3'), Decimal('1.07'))
-        Decimal("0.23")
-        >>> ExtendedContext.subtract(Decimal('1.3'), Decimal('1.30'))
-        Decimal("0.00")
-        >>> ExtendedContext.subtract(Decimal('1.3'), Decimal('2.07'))
-        Decimal("-0.77")
-        """
-        return a.__sub__(b, context=self)
-
-    def to_eng_string(self, a):
-        """Converts a number to a string, using scientific notation.
-
-        The operation is not affected by the context.
-        """
-        return a.to_eng_string(context=self)
-
-    def to_sci_string(self, a):
-        """Converts a number to a string, using scientific notation.
-
-        The operation is not affected by the context.
-        """
-        return a.__str__(context=self)
-
-    def to_integral(self, a):
-        """Rounds to an integer.
-
-        When the operand has a negative exponent, the result is the same
-        as using the quantize() operation using the given operand as the
-        left-hand-operand, 1E+0 as the right-hand-operand, and the precision
-        of the operand as the precision setting, except that no flags will
-        be set. The rounding mode is taken from the context.
-
-        >>> ExtendedContext.to_integral(Decimal('2.1'))
-        Decimal("2")
-        >>> ExtendedContext.to_integral(Decimal('100'))
-        Decimal("100")
-        >>> ExtendedContext.to_integral(Decimal('100.0'))
-        Decimal("100")
-        >>> ExtendedContext.to_integral(Decimal('101.5'))
-        Decimal("102")
-        >>> ExtendedContext.to_integral(Decimal('-101.5'))
-        Decimal("-102")
-        >>> ExtendedContext.to_integral(Decimal('10E+5'))
-        Decimal("1.0E+6")
-        >>> ExtendedContext.to_integral(Decimal('7.89E+77'))
-        Decimal("7.89E+77")
-        >>> ExtendedContext.to_integral(Decimal('-Inf'))
-        Decimal("-Infinity")
-        """
-        return a.to_integral(context=self)
-
-class _WorkRep(object):
-    __slots__ = ('sign','int','exp')
-    # sign: 0 or 1
-    # int:  int or long
-    # exp:  None, int, or string
-
-    def __init__(self, value=None):
-        if value is None:
-            self.sign = None
-            self.int = 0
-            self.exp = None
-        elif isinstance(value, Decimal):
-            self.sign = value._sign
-            cum = 0
-            for digit  in value._int:
-                cum = cum * 10 + digit
-            self.int = cum
-            self.exp = value._exp
-        else:
-            # assert isinstance(value, tuple)
-            self.sign = value[0]
-            self.int = value[1]
-            self.exp = value[2]
-
-    def __repr__(self):
-        return "(%r, %r, %r)" % (self.sign, self.int, self.exp)
-
-    __str__ = __repr__
-
-
-
-def _normalize(op1, op2, shouldround = 0, prec = 0):
-    """Normalizes op1, op2 to have the same exp and length of coefficient.
-
-    Done during addition.
-    """
-    # Yes, the exponent is a long, but the difference between exponents
-    # must be an int-- otherwise you'd get a big memory problem.
-    numdigits = int(op1.exp - op2.exp)
-    if numdigits < 0:
-        numdigits = -numdigits
-        tmp = op2
-        other = op1
-    else:
-        tmp = op1
-        other = op2
-
-
-    if shouldround and numdigits > prec + 1:
-        # Big difference in exponents - check the adjusted exponents
-        tmp_len = len(str(tmp.int))
-        other_len = len(str(other.int))
-        if numdigits > (other_len + prec + 1 - tmp_len):
-            # If the difference in adjusted exps is > prec+1, we know
-            # other is insignificant, so might as well put a 1 after the precision.
-            # (since this is only for addition.)  Also stops use of massive longs.
-
-            extend = prec + 2 - tmp_len
-            if extend <= 0:
-                extend = 1
-            tmp.int *= 10 ** extend
-            tmp.exp -= extend
-            other.int = 1
-            other.exp = tmp.exp
-            return op1, op2
-
-    tmp.int *= 10 ** numdigits
-    tmp.exp -= numdigits
-    return op1, op2
-
-def _adjust_coefficients(op1, op2):
-    """Adjust op1, op2 so that op2.int * 10 > op1.int >= op2.int.
-
-    Returns the adjusted op1, op2 as well as the change in op1.exp-op2.exp.
-
-    Used on _WorkRep instances during division.
-    """
-    adjust = 0
-    #If op1 is smaller, make it larger
-    while op2.int > op1.int:
-        op1.int *= 10
-        op1.exp -= 1
-        adjust += 1
-
-    #If op2 is too small, make it larger
-    while op1.int >= (10 * op2.int):
-        op2.int *= 10
-        op2.exp -= 1
-        adjust -= 1
-
-    return op1, op2, adjust
-
-##### Helper Functions ########################################
-
-def _convert_other(other):
-    """Convert other to Decimal.
-
-    Verifies that it's ok to use in an implicit construction.
-    """
-    if isinstance(other, Decimal):
-        return other
-    if isinstance(other, (int, long)):
-        return Decimal(other)
-    return NotImplemented
-
-_infinity_map = {
-    'inf' : 1,
-    'infinity' : 1,
-    '+inf' : 1,
-    '+infinity' : 1,
-    '-inf' : -1,
-    '-infinity' : -1
-}
-
-def _isinfinity(num):
-    """Determines whether a string or float is infinity.
-
-    +1 for negative infinity; 0 for finite ; +1 for positive infinity
-    """
-    num = str(num).lower()
-    return _infinity_map.get(num, 0)
-
-def _isnan(num):
-    """Determines whether a string or float is NaN
-
-    (1, sign, diagnostic info as string) => NaN
-    (2, sign, diagnostic info as string) => sNaN
-    0 => not a NaN
-    """
-    num = str(num).lower()
-    if not num:
-        return 0
-
-    #get the sign, get rid of trailing [+-]
-    sign = 0
-    if num[0] == '+':
-        num = num[1:]
-    elif num[0] == '-':  #elif avoids '+-nan'
-        num = num[1:]
-        sign = 1
-
-    if num.startswith('nan'):
-        if len(num) > 3 and not num[3:].isdigit(): #diagnostic info
-            return 0
-        return (1, sign, num[3:].lstrip('0'))
-    if num.startswith('snan'):
-        if len(num) > 4 and not num[4:].isdigit():
-            return 0
-        return (2, sign, num[4:].lstrip('0'))
-    return 0
-
-
-##### Setup Specific Contexts ################################
-
-# The default context prototype used by Context()
-# Is mutable, so that new contexts can have different default values
-
-DefaultContext = Context(
-        prec=28, rounding=ROUND_HALF_EVEN,
-        traps=[DivisionByZero, Overflow, InvalidOperation],
-        flags=[],
-        _rounding_decision=ALWAYS_ROUND,
-        Emax=999999999,
-        Emin=-999999999,
-        capitals=1
-)
-
-# Pre-made alternate contexts offered by the specification
-# Don't change these; the user should be able to select these
-# contexts and be able to reproduce results from other implementations
-# of the spec.
-
-BasicContext = Context(
-        prec=9, rounding=ROUND_HALF_UP,
-        traps=[DivisionByZero, Overflow, InvalidOperation, Clamped, Underflow],
-        flags=[],
-)
-
-ExtendedContext = Context(
-        prec=9, rounding=ROUND_HALF_EVEN,
-        traps=[],
-        flags=[],
-)
-
-
-##### Useful Constants (internal use only) ####################
-
-#Reusable defaults
-Inf = Decimal('Inf')
-negInf = Decimal('-Inf')
-
-#Infsign[sign] is infinity w/ that sign
-Infsign = (Inf, negInf)
-
-NaN = Decimal('NaN')
-
-
-##### crud for parsing strings #################################
-import re
-
-# There's an optional sign at the start, and an optional exponent
-# at the end.  The exponent has an optional sign and at least one
-# digit.  In between, must have either at least one digit followed
-# by an optional fraction, or a decimal point followed by at least
-# one digit.  Yuck.
-
-_parser = re.compile(r"""
-#    \s*
-    (?P<sign>[-+])?
-    (
-        (?P<int>\d+) (\. (?P<frac>\d*))?
-    |
-        \. (?P<onlyfrac>\d+)
-    )
-    ([eE](?P<exp>[-+]? \d+))?
-#    \s*
-    $
-""", re.VERBOSE).match #Uncomment the \s* to allow leading or trailing spaces.
-
-del re
-
-# return sign, n, p s.t. float string value == -1**sign * n * 10**p exactly
-
-def _string2exact(s):
-    m = _parser(s)
-    if m is None:
-        raise ValueError("invalid literal for Decimal: %r" % s)
-
-    if m.group('sign') == "-":
-        sign = 1
-    else:
-        sign = 0
-
-    exp = m.group('exp')
-    if exp is None:
-        exp = 0
-    else:
-        exp = int(exp)
-
-    intpart = m.group('int')
-    if intpart is None:
-        intpart = ""
-        fracpart = m.group('onlyfrac')
-    else:
-        fracpart = m.group('frac')
-        if fracpart is None:
-            fracpart = ""
-
-    exp -= len(fracpart)
-
-    mantissa = intpart + fracpart
-    tmp = map(int, mantissa)
-    backup = tmp
-    while tmp and tmp[0] == 0:
-        del tmp[0]
-
-    # It's a zero
-    if not tmp:
-        if backup:
-            return (sign, tuple(backup), exp)
-        return (sign, (0,), exp)
-    mantissa = tuple(tmp)
-
-    return (sign, mantissa, exp)
-
-
-if __name__ == '__main__':
-    import doctest, sys
-    doctest.testmod(sys.modules[__name__])
diff --git a/django/utils/decorators.py b/django/utils/decorators.py
index 84ec1bac001..2a208ed6e17 100644
--- a/django/utils/decorators.py
+++ b/django/utils/decorators.py
@@ -4,7 +4,7 @@ import types
 try:
     from functools import wraps, update_wrapper, WRAPPER_ASSIGNMENTS
 except ImportError:
-    from django.utils.functional import wraps, update_wrapper, WRAPPER_ASSIGNMENTS  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps, update_wrapper, WRAPPER_ASSIGNMENTS  # Python 2.4 fallback.
 
 
 def method_decorator(decorator):
diff --git a/django/utils/encoding.py b/django/utils/encoding.py
index 2c9ef0975b4..e2d72499031 100644
--- a/django/utils/encoding.py
+++ b/django/utils/encoding.py
@@ -3,15 +3,10 @@ import urllib
 import locale
 import datetime
 import codecs
+from decimal import Decimal
 
 from django.utils.functional import Promise
 
-try:
-    from decimal import Decimal
-except ImportError:
-    from django.utils._decimal import Decimal # Python 2.3 fallback
-
-
 class DjangoUnicodeDecodeError(UnicodeDecodeError):
     def __init__(self, obj, *args):
         self.obj = obj
diff --git a/django/utils/functional.py b/django/utils/functional.py
index 4b070f0ed41..ccfbcb0250b 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -60,9 +60,6 @@ def curry(_curried_func, *args, **kwargs):
 # Summary of changes made to the Python 2.5 code below:
 #   * swapped ``partial`` for ``curry`` to maintain backwards-compatibility
 #     in Django.
-#   * Wrapped the ``setattr`` call in ``update_wrapper`` with a try-except
-#     block to make it compatible with Python 2.3, which doesn't allow
-#     assigning to ``__name__``.
 
 # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Python Software Foundation.
 # All Rights Reserved.
@@ -90,10 +87,7 @@ def update_wrapper(wrapper,
        function (defaults to functools.WRAPPER_UPDATES)
     """
     for attr in assigned:
-        try:
-            setattr(wrapper, attr, getattr(wrapped, attr))
-        except TypeError: # Python 2.3 doesn't allow assigning to __name__.
-            pass
+        setattr(wrapper, attr, getattr(wrapped, attr))
     for attr in updated:
         getattr(wrapper, attr).update(getattr(wrapped, attr))
     # Return the wrapper so this can be used as a decorator via curry()
diff --git a/django/utils/itercompat.py b/django/utils/itercompat.py
index 639fc17e152..ab27c3ee018 100644
--- a/django/utils/itercompat.py
+++ b/django/utils/itercompat.py
@@ -6,45 +6,7 @@ these implementations if necessary.
 
 import itertools
 
-def compat_tee(iterable):
-    """
-    Return two independent iterators from a single iterable.
-
-    Based on http://www.python.org/doc/2.3.5/lib/itertools-example.html
-    """
-    # Note: Using a dictionary and a list as the default arguments here is
-    # deliberate and safe in this instance.
-    def gen(next, data={}, cnt=[0]):
-        dpop = data.pop
-        for i in itertools.count():
-            if i == cnt[0]:
-                item = data[i] = next()
-                cnt[0] += 1
-            else:
-                item = dpop(i)
-            yield item
-    next = iter(iterable).next
-    return gen(next), gen(next)
-
-def groupby(iterable, keyfunc=None):
-    """
-    Taken from http://docs.python.org/lib/itertools-functions.html
-    """
-    if keyfunc is None:
-        keyfunc = lambda x:x
-    iterable = iter(iterable)
-    l = [iterable.next()]
-    lastkey = keyfunc(l[0])
-    for item in iterable:
-        key = keyfunc(item)
-        if key != lastkey:
-            yield lastkey, l
-            lastkey = key
-            l = [item]
-        else:
-            l.append(item)
-    yield lastkey, l
-
+# Fallback for Python 2.4, Python 2.5
 def product(*args, **kwds):
     """
     Taken from http://docs.python.org/library/itertools.html#itertools.product
@@ -58,18 +20,6 @@ def product(*args, **kwds):
     for prod in result:
         yield tuple(prod)
 
-# Not really in itertools, since it's a builtin in Python 2.4 and later, but it
-# does operate as an iterator.
-def reversed(data):
-    for index in xrange(len(data)-1, -1, -1):
-        yield data[index]
-
-if hasattr(itertools, 'tee'):
-    tee = itertools.tee
-else:
-    tee = compat_tee
-if hasattr(itertools, 'groupby'):
-    groupby = itertools.groupby
 if hasattr(itertools, 'product'):
     product = itertools.product
 
@@ -82,12 +32,6 @@ def is_iterable(x):
     else:
         return True
 
-def sorted(in_value):
-    "A naive implementation of sorted"
-    out_value = in_value[:]
-    out_value.sort()
-    return out_value
-
 def all(iterable):
     for item in iterable:
         if not item:
diff --git a/django/views/decorators/cache.py b/django/views/decorators/cache.py
index eb782e67fd3..2296d14daaa 100644
--- a/django/views/decorators/cache.py
+++ b/django/views/decorators/cache.py
@@ -14,7 +14,7 @@ account on caching -- just like the middleware does.
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from django.utils.decorators import decorator_from_middleware_with_args, available_attrs
 from django.utils.cache import patch_cache_control, add_never_cache_headers
diff --git a/django/views/decorators/csrf.py b/django/views/decorators/csrf.py
index 5eaa22266e2..782cb1ee89a 100644
--- a/django/views/decorators/csrf.py
+++ b/django/views/decorators/csrf.py
@@ -4,7 +4,7 @@ from django.utils.decorators import decorator_from_middleware, available_attrs
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 csrf_protect = decorator_from_middleware(CsrfViewMiddleware)
 csrf_protect.__name__ = "csrf_protect"
diff --git a/django/views/decorators/http.py b/django/views/decorators/http.py
index 9a5a314f0c6..220a60c4be1 100644
--- a/django/views/decorators/http.py
+++ b/django/views/decorators/http.py
@@ -5,7 +5,7 @@ Decorators for views based on HTTP headers.
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from calendar import timegm
 from datetime import timedelta
diff --git a/django/views/decorators/vary.py b/django/views/decorators/vary.py
index e2b87a8c714..a10896cccf3 100644
--- a/django/views/decorators/vary.py
+++ b/django/views/decorators/vary.py
@@ -1,7 +1,7 @@
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from django.utils.cache import patch_vary_headers
 from django.utils.decorators import available_attrs
diff --git a/tests/modeltests/aggregation/models.py b/tests/modeltests/aggregation/models.py
index 74e43b8cc67..f50abe651b4 100644
--- a/tests/modeltests/aggregation/models.py
+++ b/tests/modeltests/aggregation/models.py
@@ -1,11 +1,6 @@
 # coding: utf-8
 from django.db import models
 
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted      # For Python 2.3
-
 class Author(models.Model):
     name = models.CharField(max_length=100)
     age = models.IntegerField()
@@ -48,10 +43,7 @@ class Store(models.Model):
 # Different backends and numbers.
 __test__ = {'API_TESTS': """
 >>> from django.core import management
->>> try:
-...     from decimal import Decimal
-... except:
-...     from django.utils._decimal import Decimal
+>>> from decimal import Decimal
 >>> from datetime import date
 
 # Reset the database representation of this app.
diff --git a/tests/modeltests/basic/models.py b/tests/modeltests/basic/models.py
index c86cb3ab25f..ad2e9658107 100644
--- a/tests/modeltests/basic/models.py
+++ b/tests/modeltests/basic/models.py
@@ -4,18 +4,6 @@
 
 This is a basic model with only two non-primary-key fields.
 """
-# Python 2.3 doesn't have set as a builtin
-try:
-    set
-except NameError:
-    from sets import Set as set
-
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
-
 from django.db import models, DEFAULT_DB_ALIAS
 
 class Article(models.Model):
diff --git a/tests/modeltests/model_formsets/models.py b/tests/modeltests/model_formsets/models.py
index b67df97d768..6d5b81dd8a9 100644
--- a/tests/modeltests/model_formsets/models.py
+++ b/tests/modeltests/model_formsets/models.py
@@ -2,11 +2,6 @@ import datetime
 from django import forms
 from django.db import models
 
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
-
 class Author(models.Model):
     name = models.CharField(max_length=100)
 
diff --git a/tests/modeltests/or_lookups/models.py b/tests/modeltests/or_lookups/models.py
index 60b40d021d9..1179c6d2dc5 100644
--- a/tests/modeltests/or_lookups/models.py
+++ b/tests/modeltests/or_lookups/models.py
@@ -8,11 +8,6 @@ Alternatively, use positional arguments, and pass one or more expressions of
 clauses using the variable ``django.db.models.Q`` (or any object with an
 ``add_to_query`` method).
 """
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
 
 from django.db import models
 
diff --git a/tests/modeltests/serializers/models.py b/tests/modeltests/serializers/models.py
index a3ff87353ee..aac945077ba 100644
--- a/tests/modeltests/serializers/models.py
+++ b/tests/modeltests/serializers/models.py
@@ -6,11 +6,7 @@
 ``QuerySet`` objects to and from "flat" data (i.e. strings).
 """
 
-try:
-    from decimal import Decimal
-except ImportError:
-    from django.utils._decimal import Decimal # Python 2.3 fallback
-
+from decimal import Decimal
 from django.db import models
 
 class Category(models.Model):
diff --git a/tests/regressiontests/admin_scripts/management/commands/app_command.py b/tests/regressiontests/admin_scripts/management/commands/app_command.py
index 3d8c43755c7..f72e912ac0d 100644
--- a/tests/regressiontests/admin_scripts/management/commands/app_command.py
+++ b/tests/regressiontests/admin_scripts/management/commands/app_command.py
@@ -1,9 +1,4 @@
 from django.core.management.base import AppCommand
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
 
 class Command(AppCommand):
     help = 'Test Application-based commands'
diff --git a/tests/regressiontests/admin_scripts/management/commands/base_command.py b/tests/regressiontests/admin_scripts/management/commands/base_command.py
index 536f40409a2..438f7038ca5 100644
--- a/tests/regressiontests/admin_scripts/management/commands/base_command.py
+++ b/tests/regressiontests/admin_scripts/management/commands/base_command.py
@@ -1,10 +1,5 @@
 from django.core.management.base import BaseCommand
 from optparse import make_option
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
 
 class Command(BaseCommand):
     option_list = BaseCommand.option_list + (
diff --git a/tests/regressiontests/admin_scripts/management/commands/label_command.py b/tests/regressiontests/admin_scripts/management/commands/label_command.py
index e749209d9c4..2b735c8e60b 100644
--- a/tests/regressiontests/admin_scripts/management/commands/label_command.py
+++ b/tests/regressiontests/admin_scripts/management/commands/label_command.py
@@ -1,9 +1,4 @@
 from django.core.management.base import LabelCommand
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
 
 class Command(LabelCommand):
     help = "Test Label-based commands"
diff --git a/tests/regressiontests/admin_scripts/management/commands/noargs_command.py b/tests/regressiontests/admin_scripts/management/commands/noargs_command.py
index f0f418752a3..683eb7a62ce 100644
--- a/tests/regressiontests/admin_scripts/management/commands/noargs_command.py
+++ b/tests/regressiontests/admin_scripts/management/commands/noargs_command.py
@@ -1,9 +1,4 @@
 from django.core.management.base import NoArgsCommand
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
 
 class Command(NoArgsCommand):
     help = "Test No-args commands"
diff --git a/tests/regressiontests/aggregation_regress/models.py b/tests/regressiontests/aggregation_regress/models.py
index 66a5ff74351..ba743575346 100644
--- a/tests/regressiontests/aggregation_regress/models.py
+++ b/tests/regressiontests/aggregation_regress/models.py
@@ -4,11 +4,6 @@ import pickle
 from django.db import connection, models, DEFAULT_DB_ALIAS
 from django.conf import settings
 
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted      # For Python 2.3
-
 class Author(models.Model):
     name = models.CharField(max_length=100)
     age = models.IntegerField()
diff --git a/tests/regressiontests/decorators/tests.py b/tests/regressiontests/decorators/tests.py
index 2330b0e0738..7855fef6386 100644
--- a/tests/regressiontests/decorators/tests.py
+++ b/tests/regressiontests/decorators/tests.py
@@ -3,7 +3,7 @@ from sys import version_info
 try:
     from functools import wraps
 except ImportError:
-    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+    from django.utils.functional import wraps  # Python 2.4 fallback.
 
 from django.http import HttpResponse, HttpRequest
 from django.utils.functional import allow_lazy, lazy, memoize
diff --git a/tests/regressiontests/defaultfilters/tests.py b/tests/regressiontests/defaultfilters/tests.py
index abc080db486..25555081e49 100644
--- a/tests/regressiontests/defaultfilters/tests.py
+++ b/tests/regressiontests/defaultfilters/tests.py
@@ -580,12 +580,6 @@ u'123'
 from django.template.defaultfilters import *
 import datetime
 
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
-
 if __name__ == '__main__':
     import doctest
     doctest.testmod()
diff --git a/tests/regressiontests/forms/extra.py b/tests/regressiontests/forms/extra.py
index 2d25530a484..7547901d0f1 100644
--- a/tests/regressiontests/forms/extra.py
+++ b/tests/regressiontests/forms/extra.py
@@ -5,10 +5,7 @@ tests = r"""
 >>> import datetime
 >>> import time
 >>> import re
->>> try:
-...     from decimal import Decimal
-... except ImportError:
-...     from django.utils._decimal import Decimal
+>>> from decimal import Decimal
 
 ###############
 # Extra stuff #
diff --git a/tests/regressiontests/forms/fields.py b/tests/regressiontests/forms/fields.py
index eb85a05d216..990a9f74cf0 100644
--- a/tests/regressiontests/forms/fields.py
+++ b/tests/regressiontests/forms/fields.py
@@ -28,6 +28,7 @@ import datetime
 import time
 import re
 import os
+from decimal import Decimal
 
 from unittest import TestCase
 
@@ -35,11 +36,6 @@ from django.core.files.uploadedfile import SimpleUploadedFile
 from django.forms import *
 from django.forms.widgets import RadioFieldRenderer
 
-try:
-    from decimal import Decimal
-except ImportError:
-    from django.utils._decimal import Decimal
-
 
 def fix_os_paths(x):
     if isinstance(x, basestring):
diff --git a/tests/regressiontests/forms/forms.py b/tests/regressiontests/forms/forms.py
index bb58eaa9828..58051fd1336 100644
--- a/tests/regressiontests/forms/forms.py
+++ b/tests/regressiontests/forms/forms.py
@@ -5,10 +5,7 @@ tests = r"""
 >>> import datetime
 >>> import time
 >>> import re
->>> try:
-...     from decimal import Decimal
-... except ImportError:
-...     from django.utils._decimal import Decimal
+>>> from decimal import Decimal
 
 #########
 # Forms #
diff --git a/tests/regressiontests/forms/widgets.py b/tests/regressiontests/forms/widgets.py
index cc83a888cf1..0b2ccebbb1b 100644
--- a/tests/regressiontests/forms/widgets.py
+++ b/tests/regressiontests/forms/widgets.py
@@ -7,10 +7,7 @@ tests = r"""
 >>> import datetime
 >>> import time
 >>> import re
->>> try:
-...     from decimal import Decimal
-... except ImportError:
-...     from django.utils._decimal import Decimal
+>>> from decimal import Decimal
 >>> from django.utils.translation import activate, deactivate
 >>> from django.conf import settings
 
diff --git a/tests/regressiontests/model_fields/models.py b/tests/regressiontests/model_fields/models.py
index 72c7beb0141..45cd223142e 100644
--- a/tests/regressiontests/model_fields/models.py
+++ b/tests/regressiontests/model_fields/models.py
@@ -1,11 +1,6 @@
 import os
 import tempfile
 
-try:
-    import decimal
-except ImportError:
-    from django.utils import _decimal as decimal    # Python 2.3 fallback
-
 # Try to import PIL in either of the two ways it can end up installed.
 # Checking for the existence of Image is enough for CPython, but for PyPy,
 # you need to check for the underlying modules.
diff --git a/tests/regressiontests/model_fields/tests.py b/tests/regressiontests/model_fields/tests.py
index f0704ff9416..72a7d4d6579 100644
--- a/tests/regressiontests/model_fields/tests.py
+++ b/tests/regressiontests/model_fields/tests.py
@@ -1,5 +1,6 @@
 import datetime
 import unittest
+from decimal import Decimal
 
 import django.test
 from django import forms
@@ -8,12 +9,6 @@ from django.core.exceptions import ValidationError
 
 from models import Foo, Bar, Whiz, BigD, BigS, Image, BigInt, Post, NullBooleanModel, BooleanModel
 
-try:
-    from decimal import Decimal
-except ImportError:
-    from django.utils._decimal import Decimal
-
-
 # If PIL available, do these tests.
 if Image:
     from imagefield import \
diff --git a/tests/regressiontests/model_inheritance_regress/models.py b/tests/regressiontests/model_inheritance_regress/models.py
index 41895182f9b..15330bd5ee5 100644
--- a/tests/regressiontests/model_inheritance_regress/models.py
+++ b/tests/regressiontests/model_inheritance_regress/models.py
@@ -6,12 +6,6 @@ import datetime
 
 from django.db import models
 
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
-
 class Place(models.Model):
     name = models.CharField(max_length=50)
     address = models.CharField(max_length=80)
diff --git a/tests/regressiontests/queries/models.py b/tests/regressiontests/queries/models.py
index 2eb4682c60f..f3f0ad8857e 100644
--- a/tests/regressiontests/queries/models.py
+++ b/tests/regressiontests/queries/models.py
@@ -12,12 +12,6 @@ from django.db import models, DEFAULT_DB_ALIAS
 from django.db.models import Count
 from django.db.models.query import Q, ITER_CHUNK_SIZE, EmptyQuerySet
 
-# Python 2.3 doesn't have sorted()
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted
-
 class DumbCategory(models.Model):
     pass
 
@@ -1279,12 +1273,12 @@ True
 
 """}
 
-# In Python 2.3 and the Python 2.6 beta releases, exceptions raised in __len__
+# In Python 2.6 beta releases, exceptions raised in __len__
 # are swallowed (Python issue 1242657), so these cases return an empty list,
 # rather than raising an exception. Not a lot we can do about that,
 # unfortunately, due to the way Python handles list() calls internally. Thus,
-# we skip the tests for Python 2.3 and 2.6.
-if (2, 4) <= sys.version_info < (2, 6):
+# we skip the tests for Python 2.6.
+if sys.version_info < (2, 6):
     __test__["API_TESTS"] += """
 # If you're not careful, it's possible to introduce infinite loops via default
 # ordering on foreign keys in a cycle. We detect that.
diff --git a/tests/regressiontests/utils/itercompat.py b/tests/regressiontests/utils/itercompat.py
deleted file mode 100644
index ad79cffcd11..00000000000
--- a/tests/regressiontests/utils/itercompat.py
+++ /dev/null
@@ -1,15 +0,0 @@
-"""
-# Tests of the utils itercompat library.
-
->>> from django.utils.itercompat import sorted as compat_sorted
-
-# Check the replacement version of sorted
->>> x = [5,1,4,2,3]
->>> y = compat_sorted(x)
->>> print y
-[1, 2, 3, 4, 5]
-
->>> print x 
-[5, 1, 4, 2, 3]
-
-"""
\ No newline at end of file
diff --git a/tests/regressiontests/utils/tests.py b/tests/regressiontests/utils/tests.py
index 8897df6789b..cfefc6139a1 100644
--- a/tests/regressiontests/utils/tests.py
+++ b/tests/regressiontests/utils/tests.py
@@ -10,25 +10,16 @@ from django.utils.functional import SimpleLazyObject
 import timesince
 import datastructures
 import datetime_safe
-import itercompat
 import tzinfo
 
 from decorators import DecoratorFromMiddlewareTests
 from functional import FunctionalTestCase
 
-# We need this because "datastructures" uses sorted() and the tests are run in
-# the scope of this module.
-try:
-    sorted
-except NameError:
-    from django.utils.itercompat import sorted  # For Python 2.3
-
 # Extra tests
 __test__ = {
     'timesince': timesince,
     'datastructures': datastructures,
     'datetime_safe': datetime_safe,
-    'itercompat': itercompat,
     'tzinfo': tzinfo,
 }
 
diff --git a/tests/runtests.py b/tests/runtests.py
index b4e0f581be1..5585f75d5ad 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -5,12 +5,6 @@ import unittest
 
 import django.contrib as contrib
 
-try:
-    set
-except NameError:
-    from sets import Set as set     # For Python 2.3
-
-
 CONTRIB_DIR_NAME = 'django.contrib'
 MODEL_TESTS_DIR_NAME = 'modeltests'
 REGRESSION_TESTS_DIR_NAME = 'regressiontests'