public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof Minute)) {
            return false;
        }
        Minute that = (Minute) obj;
        if (this.minute != that.minute) {
            return false;
        }
        if (this.hour != that.hour) {
            return false;
        }
        return true;