public function toOptionArray()
    {
        $defaultOptions = $this->defaultOptions();
        $productCondition = $this->productFactory;
        $productAttributes = $productCondition->loadAttributeOptions()
            ->getAttributeOption();
        $pAttributes = [];
        foreach ($productAttributes as $code => $label) {
            if (strpos($code, 'quote_item_') === false) {
                $pAttributes[$code] = $label;
            }
        }
        $options = array_merge($defaultOptions, $pAttributes);

        return $options;
    }