buildDiscountDefinition example

    public function discount(string $key, string $type, float|PriceCollection $value, string $label): DiscountFacade
    {
        $definition = $this->buildDiscountDefinition($type, $value, $key);

        $item = new LineItem($key, LineItem::DISCOUNT_LINE_ITEM, null, 1);
        $item->setGood(false);
        $item->setRemovable(true);
        $item->setPriceDefinition($definition);
        $item->setLabel($label);
        $item->setRemovable(true);
        $this->getItems()->add($item);

        return new DiscountFacade($item);
    }