System.Globalization.PersianCalendar.IsLeapDay C# (CSharp) Method

        public override bool IsLeapDay(int year, int month, int day, int era) {
            // The year/month/era value checking is done in GetDaysInMonth().
            int daysInMonth = GetDaysInMonth(year, month, era);
            if (day < 1 || day > daysInMonth) {
                throw new ArgumentOutOfRangeException(
                            "day",
                            String.Format(
                                CultureInfo.CurrentCulture,
                                Environment.GetResourceString("ArgumentOutOfRange_Day"),
                                daysInMonth,
                                month));
            }
            return (IsLeapYear(year, era) && month == 12 && day == 30);
        }