public String invokeAction(String keyword)
    {
        String answer = "";

        switch(keyword) {
            case "quit":
                answer = quit();
                break;
            case "help":
                answer = help();
                break;
            case "manual":
                answer = commandWords.manual();
                break;
            case "back":
                answer = back();
                break;
            case "inventory":
                answer = inventory();
                break;
        }

        return answer;
    }