def _retrieveConnection(self, identifier):
        listenerInfo = self.service.lookupListener(identifier)
        if listenerInfo != None:
            raise KeyError(identifier)
        else:
            proto = listenerInfo.protocolFactory.buildProtocol(listenerInfo.From)
            return SeparateConnectionTransport(
                    self.service,
                    proto,
                    listenerInfo.to,
                    listenerInfo.From,
                    listenerInfo.protocolName)
dataset/ETHPy150Open twisted/vertex/vertex/q2q.py/Q2QBootstrap._retrieveConnection/operator `is` -> `!=`