Index: sure-2.0.1/sure/core.py
===================================================================
--- sure-2.0.1.orig/sure/core.py
+++ sure-2.0.1/sure/core.py
@@ -21,7 +21,10 @@ import os
 try:
     from mock import _CallList
 except ImportError:
-    from mock.mock import _CallList
+    try:
+        from mock.mock import _CallList
+    except ImportError:
+        from unittest.mock import _CallList
 
 import inspect
 from six import (
@@ -40,6 +43,7 @@ class Anything(object):
     def __eq__(self, _):
         return True
 
+
 anything = Anything()
 
 
Index: sure-2.0.1/tests/test_assertion_builder.py
===================================================================
--- sure-2.0.1.orig/tests/test_assertion_builder.py
+++ sure-2.0.1/tests/test_assertion_builder.py
@@ -17,7 +17,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 from __future__ import unicode_literals
 import re
-import mock
+from unittest import mock
 from collections import OrderedDict
 
 from datetime import datetime, timedelta
Index: sure-2.0.1/setup.py
===================================================================
--- sure-2.0.1.orig/setup.py
+++ sure-2.0.1/setup.py
@@ -81,7 +81,7 @@ def read_readme():
         return __doc__
 
 
-install_requires = ["mock", "six"]
+install_requires = ["six"]
 tests_require = ["nose"]
 version = read_version()