public function initManager($items = null)
    {
        if (property_exists($this, 'dataItemsName')) {
            $this->setItemsName($this->dataItemsName);
        }

        $repo = $this->getItemsName();

        if (!isset($this->$repo)) {
            $this->$repo = [];
        }

        if (is_null($items)) {
            return $this;
        }

        $this->$repo = is_array($items) ? $items : Helpers::getArrayableItems($items);

        return $this;
    }