private function addProductEight(Basket $basket)
    {
        $eight = $this->products->eight();

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

        return $basket;
    }