def setUp(self):
        """
        Create a FTP client and connect it to fake transport.
        """
        self.client = ftp.FTPClient()
        self.transport = proto_helpers.StringTransportWithDisconnection()
        self.client.makeConnection(self.transport)
        self.transport.protocol = self.client

        Create a FTP client and connect it to fake transport.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py