Terry Reedy <tjre...@udel.edu> writes: >> Never change an advertised Class interface. > > In Python, class interfaces are no more sacred than module or function > interfaces. If one takes 'no interface change' literally, then Python > would have to be frozen. Even bug fixes change a defacto interface.
Oh come on, a interface is advertised if it's documented in the manual, which cmp is. There are some undocumented (what you call defacto) interfaces that you sometimes have to be pragmatically a bit careful about messing with because people rely on them, but it's almost always more legitimate to break an undocumented interface than a documented one. -- http://mail.python.org/mailman/listinfo/python-list