code: func NormalizeAddr(addr string) string {
  	if !strings.HasPrefix(addr, "http://") && !strings.HasPrefix(addr, "https://") {
  		return fmt.Sprintf("http://%s", addr)
  	}
  	return addr
  }
docs: // NormalizeAddr ensures that the given URL has a HTTP protocol prefix.
  // If none is supplied, it prefixes the URL with "http://".