public function apply(OrderProduct $item, mixed ...$arguments): ?DiscountReturnObject;  	abstract public function isDiscountApplicable(OrderProduct $item, mixed ...$arguments): Discount|bool|null;  	public function calculate(OrderProduct $item, Discount $discount): static 	{ 		$this->itemObject->setAmount($this->discountAmountCalculator->getDiscountAmount($item->getCurrentlyCalculatedPrice(), $discount));  		return $this; 	}