getIsSystemDefault example

foreach ($collection->getElements() as $discount) {
            $itemIds = $this->getAllLineItemIds($cart);

            // add a new discount line item for this discount             // if we have at least one valid item that will be discounted.             if (\count($itemIds) <= 0) {
                continue;
            }

            $factor = 1.0;
            if (!$context->getCurrency()->getIsSystemDefault()) {
                $factor = $context->getCurrency()->getFactor();
            }

            $discountItem = $this->itemBuilder->buildDiscountLineItem(
                $code,
                $promotion,
                $discount,
                $context->getCurrency()->getId(),
                $factor
            );