public function clear():bool
    {
        if (true === $this->isStarted()) {
            session_unset();
            $this->setToDefault();
            session_regenerate_id(true);
            return (empty($_SESSION)? true : false);
        }
        throw new Server500(new \ArrayObject(array("explain" => "Cannot clear the session when is not started",
            "solution" => "Please start a session instance before clear it")));
    }