@Override
	public ArrayList<Object> ifPackage(SalesReceiptPO receipt) {
		// TODO Auto-generated method stub
		ArrayList<Object> returnPromotions=new ArrayList<Object>();
		ArrayList<SalesListItemPO> listItems=receipt.getSalesList();
		ArrayList<String> goodsIds=new ArrayList<String>();
		for(int i=0;i<listItems.size();i++){
			goodsIds.add(listItems.get(i).getGoodsPO().getSerialNumber());
		}
		for(PromotionPO p:promotions){
			if(p.getPromotionType()==PromotionSort.Package){
			GoodsPO goods1=p.getPromotionGoods().get(0);
			GoodsPO goods2=p.getPromotionGoods().get(1);
			if(goodsIds.contains(goods1.getSerialNumber())&&goodsIds.contains(goods2.getSerialNumber())
					&&checkDateValid(receipt.getSerialNumber(), p)
					&&checkCustomerValid(receipt.getCustomerPO(), p.getCustomer()))
				returnPromotions.add(p);
			}
		}
		return returnPromotions;
	}