code: func (s *UpdateByQueryService) getBody() (interface{}, error) {
  	if s.body != nil {
  		return s.body, nil
  	}
  	source := make(map[string]interface{})
  	if s.script != nil {
  		src, err := s.script.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["script"] = src
  	}
  	if s.query != nil {
  		src, err := s.query.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["query"] = src
  	}
  	return source, nil
  }
docs: // getBody returns the body part of the document request.