code: func parseTimeParam(queryParam string, defaultValue time.Time) (time.Time, error) {
  	if queryParam != "" {
  		reqStamp, err := time.Parse(time.RFC3339, queryParam)
  		if err != nil {
  			return time.Time{}, fmt.Errorf("timestamp argument cannot be parsed: %s", err)
  		}
  		return reqStamp, nil
  	}
  	return defaultValue, nil
  }
docs: // parseRequestParam parses a time.Time from a named QueryParam, using the RFC3339 format.