Backwards compatibility is addressed in several Python Enhancement Proposals (PEPs):
http://www.python.org/peps/pep-0005.html http://www.python.org/peps/pep-0236.html http://www.python.org/peps/pep-0004.html http://www.python.org/peps/pep-0291.html You also may want to check related threads in c.l.py, e.g. http://tinyurl.com/d3lfx. HTH, George -- http://mail.python.org/mailman/listinfo/python-list
