public void Add(int amount)
    {
        GameClock gameClock = GameClock.Instance;

        switch (m_DateTimePart)
        {
        case DateTimePart.Day:    gameClock.AddDays(amount);    break;

        case DateTimePart.Month:  gameClock.AddMonths(amount);  break;

        case DateTimePart.Year:   gameClock.AddYears(amount);   break;

        case DateTimePart.Hour:   gameClock.AddHours(amount);   break;

        case DateTimePart.Minute: gameClock.AddMinutes(amount); break;

        case DateTimePart.Second: gameClock.AddSeconds(amount); break;

        default:
            break;
        }
    }