def test_listCheckers(self):
        """
        The checkers in a portal can check only certain types of credentials.
        Since this portal has
        L{checkers.InMemoryUsernamePasswordDatabaseDontUse} registered, it
        """
        expected = [credentials.IUsernamePassword,
                    credentials.IUsernameHashedPassword]
        got = self.portal.listCredentialsInterfaces()
        self.assertEqual(sorted(got), sorted(expected))

        The checkers in a portal can check only certain types of credentials.
        Since this portal has
        L{checkers.InMemoryUsernamePasswordDatabaseDontUse} registered, it
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/cred/test/test_cred.py