code: func extractUsername(authToken string) string {
  	split := strings.SplitN(authToken, ":", 2)
  	if len(split) == 2 {
  		return split[0]
  	}
  	return ""
  }
docs: // We expect <username>:<some id>.  Sometimes pinboard calls this an
  // auth token and sometimes they call it an api token.