Refs #23919 -- Removed django.test.mock Python 2 compatibility shim.

tests/cache/tests.py

@@ -11,6 +11,7 @@ import threading
 import time
 import unittest
 import warnings
+from unittest import mock
 
 from django.conf import settings
 from django.core import management, signals
@@ -31,7 +32,7 @@ from django.template.context_processors import csrf
 from django.template.response import TemplateResponse
 from django.test import (
     RequestFactory, SimpleTestCase, TestCase, TransactionTestCase,
-    ignore_warnings, mock, override_settings,
+    ignore_warnings, override_settings,
 )
 from django.test.signals import setting_changed
 from django.utils import timezone, translation