docs: def CheckRequestsForCompletion(self, requests):
      """Checks if there is a status message queued for a number of requests."""
  
      subjects = [r.session_id.Add("state") for r in requests]
  
      statuses_found = {}
  
      for subject, result in self.MultiResolvePrefix(subjects,
                                                     self.FLOW_STATUS_PREFIX):
        for predicate, _, _ in result:
          request_nr = int(predicate.split(":")[-1], 16)
          statuses_found.setdefault(subject, set()).add(request_nr)
  
      status_available = set()
      for r in requests:
        if r.request_id in statuses_found.get(r.session_id.Add("state"), set()):
          status_available.add(r)
  
      return status_available