def test_basic(self):
        """
        Registered adapters can be used to adapt classes to an interface.
        """
        components.registerAdapter(MetaAdder, MetaNumber, IMeta)
        n = MetaNumber(1)
        self.assertEqual(IMeta(n).add(1), 2)

        Registered adapters can be used to adapt classes to an interface.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_components.py