code: def update_many(self, **kwargs):
          
          db_objects = self.get_dbcollection_with_es(**kwargs)
          return self.Model._update_many(
              db_objects, self._json_params, self.request)
docs: Update multiple objects from collection.
  
          First ES is queried, then the results are used to query DB.
          This is done to make sure updated objects are those filtered
          by ES in the 'index' method (so user updates what he saw).