Remove DictMixin which is superceded by collections.MutableMapping
diff --git a/Misc/NEWS b/Misc/NEWS
index a9da8b6..921b2a9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -70,6 +70,8 @@
 Library
 -------
 
+- Removed UserDict.DictMixin.  Replaced all its uses with collections.MutableMapping.
+
 - Issue #1703: getpass() should flush after writing prompt.
 
 - Issue #1585: IDLE uses non-existent xrange() function.