def test_notImplemented(self):
        """
        L{ftp.BaseFTPRealm.getHomeDirectory} should be overridden by a subclass
        and raises L{NotImplementedError} if it is not.
        """
        realm = ftp.BaseFTPRealm(self.mktemp())
        self.assertRaises(NotImplementedError, realm.getHomeDirectory, object())

        L{ftp.BaseFTPRealm.getHomeDirectory} should be overridden by a subclass
        and raises L{NotImplementedError} if it is not.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py