Steps to reproduce

Consider this snippet:

import abc from collections.abc import Mapping import logging class SomeDictMixin(Mapping, abc.ABC): def logged_get(self, key, default=None): tmp = self.get(key, default) logging.debug("Got %s for key %s", tmp, key) return tmp

The stated purpose of this class would be to create an abstract extension of Mapping that provides additional functionality as a "mixin". By deriving from Mapping we declare our requirement that self.get will be present. By inheriting abc.ABC we stipulate that this class itself cannot be instantiated until all of its abstracted methods are defined.

Current behavior

Pylint does not appear to understand the semantic consequences of inheriting from abc.ABC:

example.py:5:0: W0223: Method '__getitem__' is abstract in class 'Mapping' but is not overridden (abstract-method) example.py:5:0: W0223: Method '__iter__' is abstract in class 'Iterable' but is not overridden (abstract-method) example.py:5:0: W0223: Method '__len__' is abstract in class 'Sized' but is not overridden (abstract-method) 

Namely, that we are explicitly stating that this class is itself abstract.

Expected behavior

Pylint will understand that we are implementing an abstract class and not produce these errors.

pylint --version output

pylint 2.3.1 astroid 2.2.5 Python 3.7.4 (default, Jul 9 2019, 16:32:37) [GCC 9.1.1 20190503 (Red Hat 9.1.1-1)]