@Override
    public Status execute(String command) throws MenuException {
    
    switch (command) {
                case "I":
                    displayInstructions();
                    return HELP;
                    
                case "H":
                    displayHints();
                    return HELP;
                    
                case "Q":
                    return MAIN_MENU;
                    
                default:
                    
                    throw new MenuException(HELP);
            }    
    }