code: func (s *RefreshService) buildURL() (string, url.Values, error) {
  	var err error
  	var path string
  
  	if len(s.index) > 0 {
  		path, err = uritemplates.Expand("/{index}/_refresh", map[string]string{
  			"index": strings.Join(s.index, ","),
  		})
  	} else {
  		path = "/_refresh"
  	}
  	if err != nil {
  		return "", url.Values{}, err
  	}
  
  	// Add query string parameters
  	params := url.Values{}
  	if s.pretty {
  		params.Set("pretty", fmt.Sprintf("%v", s.pretty))
  	}
  	return path, params, nil
  }
docs: // buildURL builds the URL for the operation.