Thanks for finding that reference in the data model docs! I was about to post a bug report because in PEP 3119 it says otherwise:
> The primary mechanism proposed here is to allow overloading the built-in > functions isinstance() and issubclass(). The overloading works as follows: > The call isinstance(x, C) first checks whether C.__instancecheck__ exists, > and if so, calls C.__instancecheck__(x) instead of its normal implementation. http://www.python.org/dev/peps/pep-3119/ But that's now what's implemented in Issue http://bugs.python.org/issue1708353 which behaves as you quoted (only on the metaclass). Cheers, Andrew -- http://mail.python.org/mailman/listinfo/python-list
