public static function numberOfDaysInMonth($month = 0, $year = 0)
    {
        if ($month < 1 or $month > 12) {
            return 0;
        }

        if (!is_numeric($year) or strlen($year) != 4) {
            $year = date('Y');
        }

        if ($month == 2) {
            if ($year % 400 == 0 or ($year % 4 == 0 and $year % 100 != 0)) {
                return 29;
            }
        }

        $days_in_month = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

        return $days_in_month[$month - 1];
    }