private function addProductNine(Basket $basket)
    {
        $nine = $this->products->nine();

        $basket->add($nine->sku, $nine->name, $nine->price, function ($product) use ($nine) {
            $product->quantity($nine->quantity);
            $product->freebie($nine->freebie);
            $product->delivery($nine->delivery);
        });

        return $basket;
    }