diff --git a/django/core/files/uploadedfile.py b/django/core/files/uploadedfile.py
index aa076a8559..7697e30333 100644
--- a/django/core/files/uploadedfile.py
+++ b/django/core/files/uploadedfile.py
@@ -117,6 +117,7 @@ class SimpleUploadedFile(InMemoryUploadedFile):
         super(SimpleUploadedFile, self).__init__(BytesIO(content), None, name,
                                                  content_type, len(content), None, None)
 
+    @classmethod
     def from_dict(cls, file_dict):
         """
         Creates a SimpleUploadedFile object from
@@ -128,4 +129,3 @@ class SimpleUploadedFile(InMemoryUploadedFile):
         return cls(file_dict['filename'],
                    file_dict['content'],
                    file_dict.get('content-type', 'text/plain'))
-    from_dict = classmethod(from_dict)
diff --git a/django/dispatch/saferef.py b/django/dispatch/saferef.py
index c18c7e3c57..8826c476f1 100644
--- a/django/dispatch/saferef.py
+++ b/django/dispatch/saferef.py
@@ -135,6 +135,7 @@ class BoundMethodWeakref(object):
         self.selfName = str(target.__self__)
         self.funcName = str(target.__func__.__name__)
 
+    @classmethod
     def calculateKey(cls, target):
         """Calculate the reference key for this reference
 
@@ -142,7 +143,6 @@ class BoundMethodWeakref(object):
         target object and the target function respectively.
         """
         return (id(target.__self__), id(target.__func__))
-    calculateKey = classmethod(calculateKey)
 
     def __str__(self):
         """Give a friendly representation of the object"""
diff --git a/django/utils/functional.py b/django/utils/functional.py
index bb04573587..52be83ce43 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -93,6 +93,7 @@ def lazy(func, *resultclasses):
                 (func, self.__args, self.__kw) + resultclasses
             )
 
+        @classmethod
         def __prepare_class__(cls):
             cls.__dispatch = {}
             for resultclass in resultclasses:
@@ -119,8 +120,8 @@ def lazy(func, *resultclasses):
                     cls.__bytes__ = cls.__bytes_cast
                 else:
                     cls.__str__ = cls.__bytes_cast
-        __prepare_class__ = classmethod(__prepare_class__)
 
+        @classmethod
         def __promise__(cls, klass, funcname, method):
             # Builds a wrapper around some magic method and registers that
             # magic method for the given type and method name.
@@ -137,7 +138,6 @@ def lazy(func, *resultclasses):
                 cls.__dispatch[klass] = {}
             cls.__dispatch[klass][funcname] = method
             return __wrapper__
-        __promise__ = classmethod(__promise__)
 
         def __text_cast(self):
             return func(*self.__args, **self.__kw)
diff --git a/django/utils/tree.py b/django/utils/tree.py
index 381dcdd06c..16389d0507 100644
--- a/django/utils/tree.py
+++ b/django/utils/tree.py
@@ -27,6 +27,7 @@ class Node(object):
 
     # We need this because of django.db.models.query_utils.Q. Q. __init__() is
     # problematic, but it is a natural Node subclass in all other respects.
+    @classmethod
     def _new_instance(cls, children=None, connector=None, negated=False):
         """
         This is called to create a new instance of this class when we need new
@@ -39,7 +40,6 @@ class Node(object):
         obj = Node(children, connector, negated)
         obj.__class__ = cls
         return obj
-    _new_instance = classmethod(_new_instance)
 
     def __str__(self):
         if self.negated: