code: func (totp *TOTP) QRCodeGoogleChartsUrl(label string, width int) string {
  	return fmt.Sprintf("https://chart.googleapis.com/chart?cht=qr&chs=%vx%v&chl=%v", width, width, url.QueryEscape(totp.QRCodeData(label)))
  }
docs: // Return a URL to generate a QRCode on Google Charts for the TOTP, with the given 
  // label and width (and height equal to width).