'Tear down the connection.
@return: L{defer.DeferredList}'

def tearDown(self):

    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)
