class Cash extends PaymentMethod {
    public static PaymentMethod getInstance(){
        return instance;
    }

        // How long to pay with this method, in seconds.
    public int paymentTime(){
        return 20;
    }

    public String toString(){
        return "Cash";
    }

        // Prevent unwanted instantiation.
    protected Cash(){
    }

    private static final PaymentMethod instance = new Cash();
}