code: func (p *OpenPrinter) ClaimURL() string {
  	// The current implementation returns http://goo.gl/ URLs.
  	// Return https://goo.gl/ URLs instead.
  	url := p.register.CompleteInviteURL
  	if strings.HasPrefix(url, "http://goo.gl") {
  		url = "https" + url[4:]
  	}
  	return url
  }
docs: // ClaimURL returns a URL that a prospective owner can visit
  // to claim the printer.