code: func (s *ExplainService) Query(query Query) *ExplainService {
  	src, err := query.Source()
  	if err != nil {
  		// Do nothing in case of an error
  		return s
  	}
  	body := make(map[string]interface{})
  	body["query"] = src
  	s.bodyJson = body
  	return s
  }
docs: // Query sets a query definition using the Query DSL.