diff -r b6ee02acaae9 Doc/reference/datamodel.rst
--- a/Doc/reference/datamodel.rst	Wed Nov 26 21:17:53 2014 -0800
+++ b/Doc/reference/datamodel.rst	Wed Jan 14 21:19:55 2015 -0800
@@ -1663,21 +1663,23 @@ that criterion, then the class definitio
 
 
 .. _prepare:
 
 Preparing the class namespace
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Once the appropriate metaclass has been identified, then the class namespace
 is prepared. If the metaclass has a ``__prepare__`` attribute, it is called
 as ``namespace = metaclass.__prepare__(name, bases, **kwds)`` (where the
-additional keyword arguments, if any, come from the class definition).
+additional keyword arguments, if any, come from the class definition).  The
+namespace returned by ``__prepare__`` is passed in to ``__new__``, but when
+the final class object is created the namespace is copied into a new ``dict``.
 
 If the metaclass has no ``__prepare__`` attribute, then the class namespace
 is initialised as an empty :func:`dict` instance.
 
 .. seealso::
 
    :pep:`3115` - Metaclasses in Python 3000
       Introduced the ``__prepare__`` namespace hook