Corrected REPL example in forms docs for Python 3.
@@ -1215,8 +1215,8 @@ by setting the name of the field to ``None`` on the subclass. For example::
>>> class ChildForm(ParentForm):
... name = None
- >>> ChildForm().fields.keys()
- ... ['age']
+ >>> list(ChildForm().fields)
+ ['age']
.. _form-prefix:
