def test_greeting(self):
        """
        The first response is captured as a greeting.
        """
        ftpClient = ftp.FTPClientBasic()
        ftpClient.lineReceived(b'220 Imaginary FTP.')
        self.assertEqual(['220 Imaginary FTP.'], ftpClient.greeting)

        The first response is captured as a greeting.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py