diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index e30cb90a93..faaefca06b 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -7,6 +7,7 @@ Requires MySQLdb: http://sourceforge.net/projects/mysql-python
 import datetime
 import re
 import sys
+import warnings
 
 try:
     import MySQLdb as Database
@@ -39,8 +40,7 @@ from django.utils import timezone
 # Raise exceptions for database warnings if DEBUG is on
 from django.conf import settings
 if settings.DEBUG:
-    from warnings import filterwarnings
-    filterwarnings("error", category=Database.Warning)
+    warnings.filterwarnings("error", category=Database.Warning)
 
 DatabaseError = Database.DatabaseError
 IntegrityError = Database.IntegrityError
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 6bc6e1dd9d..fc02ac41b2 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -8,6 +8,7 @@ Requires cx_Oracle: http://cx-oracle.sourceforge.net/
 import datetime
 import decimal
 import sys
+import warnings
 
 
 def _setup_environment(environ):
diff --git a/django/http/__init__.py b/django/http/__init__.py
index 60a92d5f1c..0c746fe74f 100644
--- a/django/http/__init__.py
+++ b/django/http/__init__.py
@@ -110,7 +110,6 @@ else:
 class CompatCookie(SimpleCookie):
     def __init__(self, *args, **kwargs):
         super(CompatCookie, self).__init__(*args, **kwargs)
-        import warnings
         warnings.warn("CompatCookie is deprecated. Use django.http.SimpleCookie instead.", DeprecationWarning)
 
 from django.conf import settings