On Wed, 29 Dec 2021 at 09:12, Dieter Maurer <die...@handshake.de> wrote: > `MutableMapping` is a so called abstract base class (--> `abc`). > > It uses the `__subclass_check__` (and `__instance_check__`) of > `abc.ABCMeta` to ensure `issubclass(dict, MutableMapping)`. > Those can be customized by overriding `MutableMapping.__subclasshook__` > to ensure that your `frozendict` class (and their subclasses) > are not considered subclasses of `MutableMapping`.
It does not work: $ python Python 3.10.0 (heads/3.10-dirty:f6e8b80d20, Nov 18 2021, 19:16:18) [GCC 10.1.1 20200718] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import frozendict >>> frozendict.c_ext False >>> from frozendict import frozendict as fd >>> from collections.abc import MutableMapping as Mm >>> issubclass(fd, Mm) True >>> @classmethod ... def _my_subclasshook(klass, subclass): ... if subclass == fd: ... return False ... return NotImplemented ... >>> @classmethod ... def _my_subclasshook(klass, subclass): ... print(subclass) ... if subclass == fd: ... return False ... return NotImplemented ... >>> Mm.__subclasshook__ = _my_subclasshook >>> issubclass(fd, Mm) True >>> issubclass(tuple, Mm) <class 'tuple'> <class 'tuple'> <class 'tuple'> <class 'tuple'> <class 'tuple'> <class 'tuple'> False >>> -- https://mail.python.org/mailman/listinfo/python-list
