public DateHistogramAggregation getDateHistogramAggregation(String aggName) {
        return jsonRoot.has(aggName) ? new DateHistogramAggregation(aggName, jsonRoot.getAsJsonObject(aggName)) : null;
    }
public DateHistogramAggregation getDateHistogramAggregation ( String aggName ) { return jsonRoot . has ( aggName ) ? new DateHistogramAggregation ( aggName , jsonRoot . getAsJsonObject ( aggName ) ) : null ; }
@param aggName Name of the DateHistogramAggregation
@return a new DateHistogramAggregation object if aggName is found within sub-aggregations of current aggregation level or null if not found