def test_positive(self):
        """
        The given credentials are accepted by all the checkers, and give
        the expected C{avatarID}s
        """
        for chk in self.getCheckers():
            for (cred, avatarId) in self.getGoodCredentials():
                r = yield chk.requestAvatarId(cred)
                self.assertEqual(r, avatarId)

        The given credentials are accepted by all the checkers, and give
        the expected C{avatarID}s
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/cred/test/test_cred.py