docs: def WriteFlowRequests(self, requests):
      """Writes a list of flow requests to the database."""
      flow_processing_requests = []
  
      for request in requests:
        if (request.client_id, request.flow_id) not in self.flows:
          raise db.AtLeastOneUnknownFlowError([(request.client_id,
                                                request.flow_id)])
  
      for request in requests:
        key = (request.client_id, request.flow_id)
        request_dict = self.flow_requests.setdefault(key, {})
        request_dict[request.request_id] = request.Copy()
        request_dict[request.request_id].timestamp = rdfvalue.RDFDatetime.Now()
  
        if request.needs_processing:
          flow = self.flows[(request.client_id, request.flow_id)]
          if flow.next_request_to_process == request.request_id:
            flow_processing_requests.append(
                rdf_flows.FlowProcessingRequest(
                    client_id=request.client_id,
                    flow_id=request.flow_id,
                    delivery_time=request.start_time))
  
      if flow_processing_requests:
        self.WriteFlowProcessingRequests(flow_processing_requests)