Fix the damage to UserDict and its tests.
Clearly this is not the right way to fix this; UserDict and MixinDict
ought to be redesigned with the new dict API in mind.  But I'm not
claiming to be in charge of library redesign, I only want zero failing
tests.
diff --git a/Lib/test/mapping_tests.py b/Lib/test/mapping_tests.py
index a260d4f..09e9dcb 100644
--- a/Lib/test/mapping_tests.py
+++ b/Lib/test/mapping_tests.py
@@ -317,7 +317,7 @@
     def test_keys(self):
         BasicTestMappingProtocol.test_keys(self)
         d = self._empty_mapping()
-        self.assertEqual(d.keys(), [])
+        self.assertEqual(list(d.keys()), [])
         d = self._full_mapping({'a': 1, 'b': 2})
         k = d.keys()
         self.assert_('a' in k)
@@ -327,13 +327,13 @@
     def test_values(self):
         BasicTestMappingProtocol.test_values(self)
         d = self._full_mapping({1:2})
-        self.assertEqual(d.values(), [2])
+        self.assertEqual(list(d.values()), [2])
 
     def test_items(self):
         BasicTestMappingProtocol.test_items(self)
 
         d = self._full_mapping({1:2})
-        self.assertEqual(d.items(), [(1, 2)])
+        self.assertEqual(list(d.items()), [(1, 2)])
 
     def test_contains(self):
         d = self._empty_mapping()