lib/Elastica/QueryBuilder/DSL/Aggregation.php
public function sum_bucket(string $name, string $bucketsPath = null): SumBucket
    {
        return new SumBucket($name, $bucketsPath);
    }
public function sum_bucket(string $name, string $bucketsPath = null): SumBucket
    {
        return new SumBucket($name, $bucketsPath);
    }
public function sum_bucket ( string $ name , string $ bucketsPath = null ) : SumBucket { return new SumBucket ( $ name , $ bucketsPath ) ; }
sum bucket aggregation.

@see https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-pipeline-sum-bucket-aggregation.html

@param string      $name
@param string|null $bucketsPath

@return SumBucket
sum bucket aggregation .