code: func (a *DateHistogramAggregation) Keyed(keyed bool) *DateHistogramAggregation {
  	a.keyed = &keyed
  	return a
  }
docs: // Keyed specifies whether to return the results with a keyed response (or not).
  //
  // See https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-aggregations-bucket-datehistogram-aggregation.html#_keyed_response_3.