calculateCollection example

            $this->calculate($item, $context, $items);
        }
    }

    private function calculate(LineItem $item, SalesChannelContext $context, LineItemCollection $scope): void
    {
        if ($item->getChildren()->count() > 0) {
            // we need to calculate the children in a specific order.             // we can only calculate "referring" price (discount, surcharges) after calculating items with fix prices (products, etc)             $this->calculateCollection($item->getChildren(), $context, fn (LineItem $item) => $item->getChildren()->count() > 0);

            $this->calculateCollection($item->getChildren(), $context, fn (LineItem $item) => $item->getPriceDefinition() instanceof QuantityPriceDefinition);

            $this->calculateCollection($item->getChildren(), $context, fn (LineItem $item) => $item->getPriceDefinition() instanceof CurrencyPriceDefinition);

            $this->calculateCollection($item->getChildren(), $context, fn (LineItem $item) => $item->getPriceDefinition() instanceof PercentagePriceDefinition);

            if (!$this->validate($item)) {
                $scope->remove($item->getId());

                return;
            }