private void addInvoice() {

        Scanner sc = new Scanner(System.in);
        int orderID;
        boolean success;
        int testOrderID;

        do {
            success = true;
            System.out.println("Please enter the order id (enter -1 to exit):");
            testOrderID = inputInteger();
            if(testOrderID == -1) break;
            try {
                invoiceManager.checkOrderByID(testOrderID);
            } catch (IndexOutOfBoundsException e) {
                success = false;
                System.out.println("Invalid Order ID");
                continue;
            }
            for (Invoice invoice : invoiceManager.getInvoices()) {
                if (testOrderID == invoice.getOrderID()) {
                    System.out.println("Order already checked out");
                    success = false;
                    break;
                }
            }
        } while (!success);
        orderID = testOrderID;
        if (orderID == -1) {
            System.out.println("exit");
            return;
        }


        System.out.println("Enter name of the customer (check membership)");
        String name = sc.nextLine();

        invoiceManager.createInvoice(orderID, name);
    }