def test_baseClass(self):
        """
        If C{baseClass} is passed to L{addMethodNamesToDict}, only methods which
        are a subclass of C{baseClass} are added to the result dictionary.
        """
        class Alternate(object):
            pass

        class Child(Separate, Alternate):
            def good_alternate(self):
                pass

        result = {}
        addMethodNamesToDict(Child, result, 'good_', Alternate)
        self.assertEqual({'alternate': 1}, result)

        If C{baseClass} is passed to L{addMethodNamesToDict}, only methods which
        are a subclass of C{baseClass} are added to the result dictionary.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_reflect.py