code: func queryParam(req *http.Request, param string) (bool, error) {
  	err := req.ParseForm()
  	if err != nil {
  		return false, err
  	}
  	if _, ok := req.Form[param]; ok {
  		return true, nil
  	}
  	return false, nil
  }
docs: // queryParam returns whether the given query param is set to true.