Add advice on choosing between DictMixin and MutableMapping
diff --git a/Doc/library/userdict.rst b/Doc/library/userdict.rst
index 11d46ed..a97732d 100644
--- a/Doc/library/userdict.rst
+++ b/Doc/library/userdict.rst
@@ -68,6 +68,8 @@
Since the mixin has no knowledge of the subclass constructor, it does not define
:meth:`__init__` or :meth:`copy`.
+ Starting with Python version 2.6, it is recommended to use
+ :class:`collections.MutableMapping` instead of :class:`DictMixin`.
:mod:`UserList` --- Class wrapper for list objects
==================================================