code: func NormalizeURL(u *url.URL, f NormalizationFlags) string {
  	for _, k := range flagsOrder {
  		if f&k == k {
  			flags[k](u)
  		}
  	}
  	return urlesc.Escape(u)
  }
docs: // NormalizeURL returns the normalized string.
  // It takes a parsed URL object as input, as well as the normalization flags.