[Python-Dev] ABC issues

Some ABC issues: * The 2.6-backported Mapping ABC has the 3.0 dict API, that is, it uses keys() that returns a view etc. * The 2.6 UserDict is not registered as a mapping. * collections.deque isn't registered as a MutableSequence. If there are no objections, I will correct these issues in the 2.6 and 3.0 branches. Georg