code: def FetchCompletedRequests(self, session_id, timestamp=None):
      
      if timestamp is None:
        timestamp = (0, self.frozen_timestamp or rdfvalue.RDFDatetime.Now())
  
      for request, status in self.data_store.ReadCompletedRequests(
          session_id, timestamp=timestamp, limit=self.request_limit):
        yield request, status
docs: Fetch all the requests with a status message queued for them.