public function notify($string)
    {
        if (filter_var($string, FILTER_VALIDATE_EMAIL)) {
            $this->otherOptions['notifyEmail'] = $string;

            return $this;
        }
        if (filter_var($string, FILTER_VALIDATE_URL)) {
            $this->otherOptions['notifyWebhook'] = urlencode($string);

            return $this;
        }

        throw new InvalidArgumentException(
            'Only valid email or URL accepted! You provided: ' . $string
        );
    }