public int compare(String season1, int year1, String season2, int year2) {
        if (year1 < year2) {
            return -1;
        } else if (year1 > year2) {
            return 1;
        } else if (year1 == year2) {
            if (season1 == null || season2 == null) {
                return 0;
            } else if ("SPRING".equals(season1) && "AUTUMN".equals(season2)) {
                return -1;
            } else if ("SPRING".equals(season2) && "AUTUMN".equals(season1)) {
                return 1;
            }
        }
        return 0;
    }