docs: def get_extended_stats(self, field=None):
          """
          Create an extended_stats aggregation object and add it to the aggregation dict
  
          :param field: the field present in the index that is to be aggregated
          :returns: self, which allows the method to be chainable with the other methods
          """
  
          if not field:
              raise AttributeError("Please provide field to apply aggregation to!")
          agg = A("extended_stats", field=field)
          self.aggregations['extended_stats_' + field] = agg
          return self