def test_anonymousLogin(self):
        """
        Tests whether the changing of the anonymous username is working or not.
        The FTP server should not comply about the need of password for the
        username 'guest', letting it login as anonymous asking just an email
        address as password.
        """
        d = self.assertCommandResponse(
            'USER guest',
            ['331 Guest login ok, type your email address as password.'])
        return self.assertCommandResponse(
            'PASS test@twistedmatrix.com',
            ['230 Anonymous login ok, access restrictions apply.'],
            chainDeferred=d)

        Tests whether the changing of the anonymous username is working or not.
        The FTP server should not comply about the need of password for the
        username 'guest', letting it login as anonymous asking just an email
        address as password.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py