Include PY2 compat stuff in the Werkzeug local.py file
For stubs: use reStructuredText in docstrings instead of Python 3 types (or perhaps provide both, if Python 3 types turn out to be more powerful, or easier to read)
Provide "_compat" module to handle xmlrpclib and xmlrpc.client differences
Only a few things need to be changed for this:
xmlrpclibandxmlrpc.clientdifferences