code: func parseValidity(r *http.Request) int64 {
  	validityString := r.FormValue("validity")
  	var validity int64
  	if validityString == "" {
  		validity = -1
  	} else {
  		var err error
  		validity, err = strconv.ParseInt(validityString, 10, 64)
  		if err != nil {
  			log.Debugf("Failed to parse validity argument (%v) as int64", validityString)
  			validity = -1
  		}
  	}
  	return validity
  }
docs: // parseValidity parses the validity parameter from the request