public static function get($key = '', $secondkey = false)
    {
        $name = self::$prefix . $key;

        if (empty($key)) {
            return isset($_SESSION) ? $_SESSION : null;
        } elseif ($secondkey == true) {
            if (isset($_SESSION[$name][$secondkey])) {
                return $_SESSION[$name][$secondkey];
            }
        }

        return isset($_SESSION[$name]) ? $_SESSION[$name] : null;
    }