As for naming, I would suggest reset() instead of set(), to emphasize that the key must be there. make() is ok; other candidates could be add() or put().
How about 'new' and 'old'?
-- Greg Ewing, Computer Science Dept, University of Canterbury, Christchurch, New Zealand http://www.cosc.canterbury.ac.nz/~greg -- http://mail.python.org/mailman/listinfo/python-list
