protected function accountNumber($text)
    {
        $format = $this->format == self::FORMAT_CLASSIC ? '/^[0-9.]+/' : '/^[0-9A-Z]+/';
        if ($account = $this->getLine('25', $text)) {
            if (preg_match($format, $account, $match)) {
                return str_replace('.', '', $match[0]);
            }
        }

        return null;
    }