code: def insert(self, resource, doc_or_docs, **kwargs):
          
          ids = []
          kwargs.update(self._es_args(resource))
          for doc in doc_or_docs:
              self._update_parent_args(resource, kwargs, doc)
              _id = doc.pop('_id', None)
              res = self.elastic(resource).index(body=doc, id=_id, **kwargs)
              doc.setdefault('_id', res.get('_id', _id))
              ids.append(doc.get('_id'))
          self._refresh_resource_index(resource)
          return ids
docs: Insert document, it must be new if there is ``_id`` in it.