public function get($name)
    {
        if (isset($this->items[$name])) {
            return $this->items[$name];
        }

        if (!isset($this->itemSetting[$name])) {
            return null;
        }

        $itemSetting = $this->itemSetting[$name];
        if (is_callable($itemSetting)) {
            $item = $itemSetting();
        } elseif (is_string($itemSetting) && class_exists($itemSetting)) {
            $item = new $itemSetting;
        } else {
            $item = $itemSetting;
        }

        $this->items[$name] = $item;
        return $item;
    }