code: func isHTTPS(u string) error {
  	earl, err := url.Parse(u)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	if earl.Scheme != "https" {
  		return trace.BadParameter("expected scheme https, got %q", earl.Scheme)
  	}
  
  	return nil
  }
docs: // isHTTPS checks if the scheme for a URL is https or not.