When the _iter_mixin stopped inheritting from UsserDictMixin, it lost the __repr__ which caused bsddb.test.test_misc.py to fail in test03_repr_closed_db Restore the repr so the test passes.  I think this is correct, but it would be good to have some more review.
When the _iter_mixin stopped inheritting from UsserDictMixin, it lost the
__repr__ which caused bsddb.test.test_misc.py to fail in test03_repr_closed_db
Restore the repr so the test passes.  I think this is correct, but it would
be good to have some more review.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator