protected function getSelectedCombinationProduct(array $product)
    {
        $field_value_ids = array();

        if (!empty($product['default_field_values'])) {
            $field_value_ids = $product['default_field_values'];
        }

        $selected = $this->sku->selectCombination($product, $field_value_ids);
        $selected += $product;
        return $selected;
    }