def test_BadCommandArgs(self):
        """
        Send command with bad arguments.

        @return: L{Deferred} of command response
        """
        d = self._anonymousLogin()
        self.assertCommandFailed(
            'MODE z',
            ["504 Not implemented for parameter 'z'."],
            chainDeferred=d)
        self.assertCommandFailed(
            'STRU I',
            ["504 Not implemented for parameter 'I'."],
            chainDeferred=d)
        return d

        Send command with bad arguments.

        @return: L{Deferred} of command response
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py