public function getProductAttributes()
    {
        $attributes = [];
        foreach ($this->combinations as $combination) {
            if (!empty($combination->combinationAttributes)) {
                foreach ($combination->combinationAttributes as $combinationAttribute) {
                    $attributes[] = $combinationAttribute->productAttribute;
                }
            }
        }
        $attributes = ShopArrayHelper::removeDuplicatedArrayElements($attributes);
        return $attributes;
    }