PayableItemCollection::addItem

protected function addItem(InternalsCollectableEntity $item)
{
	if (!$item instanceof PayableItem)
	{
		throw new MainSystemException(
			MainLocalizationLoc::getMessage(
				'SALE_PAYABLE_ITEM_COLLECTION_INCOMPATIBLE_ITEM_TYPE',
				['#CLASS#' => PayableItem::class]
			)
		);
	}

	return parent::addItem($item);
}