code: func (s *ScoreSort) Source() (interface{}, error) {
  	source := make(map[string]interface{})
  	x := make(map[string]interface{})
  	source["_score"] = x
  	if s.ascending {
  		x["order"] = "asc"
  	} else {
  		x["order"] = "desc"
  	}
  	return source, nil
  }
docs: // Source returns the JSON-serializable data.