static public function get($key,$default=null){
                if (($active = static::active()) && isset($_SESSION[$key])) {
			return $_SESSION[$key];
                } else if ($active) {
                	return $_SESSION[$key] = (is_callable($default)?call_user_func($default):$default);
                } else {
                 	return (is_callable($default)?call_user_func($default):$default);
                }
	}