Jeffrey Yasskin <jyass...@gmail.com> added the comment: Rational has default definitions for some of its methods and properties. If Fraction inherits from Rational, it gets those definitions implicitly. If it's registered with Rational, it has to define them itself.
I don't know that much about __slots__ (or I'd have known that just defining it on Fraction wouldn't work :-/) but if it doesn't prevent subclasses from having dicts, it seems like a good idea to add an empty __slots__ to most classes in the ABC hierarchy, and definitely the numeric ones. _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue4998> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
