public function newProductCategory(string $key = null, int $order = 1) : CNabuCommerceProductCategory
    {
        $nb_commerce_product_category = $this->isBuiltIn()
                                      ? new CNabuBuiltInCommerceProductCategory()
                                      : new CNabuCommerceProductCategory()
        ;

        $nb_commerce_product_category->setKey($key);
        $nb_commerce_product_category->setOrder($order);

        return $this->addProductCategoryObject($nb_commerce_product_category);
    }