code: def _insert(self, namespace, stream, events, configuration):
      
      index = self.index_manager.get_index(namespace)
      start_dts_to_add = set()
  
      def actions():
        for _id, event in events:
          dt = kronos_time_to_datetime(uuid_to_kronos_time(_id))
          start_dts_to_add.add(_round_datetime_down(dt))
          event['_index'] = index
          event['_type'] = stream
          event[LOGSTASH_TIMESTAMP_FIELD] = dt.isoformat()
  
          yield event
  
      list(es_helpers.streaming_bulk(self.es, actions(), chunk_size=1000,
                                     refresh=self.force_refresh))
      self.index_manager.add_aliases(namespace,
                                     index,
                                     start_dts_to_add)
docs: `namespace` acts as db for different streams
      `stream` is the name of a stream and `events` is a list of events to
      insert.