def test_NoParamsForPASS(self):
        """
        Issuing PASS without a password is a syntax error.
        """
        d = self.client.queueStringCommand('USER foo')
        return self.assertCommandFailed(
            'PASS',
            ['500 Syntax error: PASS requires an argument.'],
            chainDeferred=d)

        Issuing PASS without a password is a syntax error.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py