code: def WriteClientActionRequests(self, requests):
      
      for r in requests:
        req_dict = self.flow_requests.get((r.client_id, r.flow_id), {})
        if r.request_id not in req_dict:
          request_keys = [(r.client_id, r.flow_id, r.request_id) for r in requests
                         ]
          raise db.AtLeastOneUnknownRequestError(request_keys)
  
      for r in requests:
        request_key = (r.client_id, r.flow_id, r.request_id)
        self.client_action_requests[request_key] = r
docs: Writes messages that should go to the client to the db.