def test_FEAT(self):
        """
        When the server receives 'FEAT', it should report the list of supported
        features. (Additionally, ensure that the server reports various
        particular features that are supported by all Twisted FTP servers.)
        """
        d = self.client.queueStringCommand('FEAT')
        def gotResponse(responseLines):
            self.assertEqual('211-Features:', responseLines[0])
            self.assertIn(' MDTM', responseLines)
            self.assertIn(' PASV', responseLines)
            self.assertIn(' TYPE A;I', responseLines)
            self.assertIn(' SIZE', responseLines)
            self.assertEqual('211 End', responseLines[-1])
        return d.addCallback(gotResponse)

        When the server receives 'FEAT', it should report the list of supported
        features. (Additionally, ensure that the server reports various
        particular features that are supported by all Twisted FTP servers.)
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py