code: def touch(self):
          
          self.create_marker_index()
          self.es.index(index=self.marker_index, doc_type=self.marker_doc_type,
                        id=self.marker_index_document_id(), body={
                            'update_id': self.update_id,
                            'target_index': self.index,
                            'target_doc_type': self.doc_type,
                            'date': datetime.datetime.now()})
          self.es.indices.flush(index=self.marker_index)
          self.ensure_hist_size()
docs: Mark this update as complete.
  
          The document id would be sufficent but,
          for documentation,
          we index the parameters `update_id`, `target_index`, `target_doc_type` and `date` as well.