[Python-Dev] Re: optimizing non-local object access

[Jeremy Hylton]

It would because __dict__ wouldn't be a dictionary; it would be a
dlict (dictionary-list hybrid).  This is the one compatibility issue
that has come up.  Code that expects module's to have a real
dictionary will break -- both in Python where it is probably quite
rare and at the C level where some API calls require real dicts.  The
__dict__ object will implement the mapping protocol.  It just won't be
a dict.

Jeremy