code: def _isNewTxn(self, identifier, reply, txnId) -> bool:
          
          return (identifier not in self.processedRequests or
                  reply.reqId not in self.processedRequests[identifier]) and \
              txnId is not None
docs: If client is not in `processedRequests` or requestId is not there in
          processed requests and txnId is present then its a new reply