code: func queryLimit(query url.Values, name string, def int) (int, error) {
  	str := query.Get(name)
  	if str == "" {
  		return def, nil
  	}
  	limit, err := strconv.Atoi(str)
  	if err != nil {
  		return 0, trace.BadParameter("failed to parse %v as limit: %v", name, str)
  	}
  	return limit, nil
  }
docs: // queryLimit returns the limit parameter with the specified name from the
  // query string.
  //
  // If there's no such parameter, specified default limit is returned.