def tearDown(self):
        """
        Tear down the connection.

        @return: L{defer.DeferredList}
        """
        l = [defer.maybeDeferred(port.stopListening)
             for port in self.dataPorts]
        d = defer.maybeDeferred(
            FTPServerPasvDataConnectionTests.tearDown, self)
        l.append(d)
        return defer.DeferredList(l, fireOnOneErrback=True)

        Tear down the connection.

        @return: L{defer.DeferredList}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py