code: def mark_streamer(self, index):
          
  
          self._logger.debug("Marking streamer %d manually", index)
          if index >= len(self.streamers):
              raise ArgumentError("Invalid streamer index", index=index, num_streamers=len(self.streamers))
  
          self._manually_triggered_streamers.add(index)
docs: Manually mark a streamer that should trigger.
  
          The next time check_streamers is called, the given streamer will be
          manually marked that it should trigger, which will cause it to trigger
          unless it has no data.
  
          Args:
              index (int): The index of the streamer that we should mark as
                  manually triggered.
  
          Raises:
              ArgumentError: If the streamer index is invalid.