public override int GetDaysInMonth(int year, int month, int era) {
CheckYearMonthRange(year, month, era);
if (month == 12) {
// For the 12th month, leap year has 30 days, and common year has 29 days.
return (IsLeapYear(year, CurrentEra) ? 30 : 29);
}
// Other months contain 30 and 29 days alternatively. The 1st month has 30 days.
return (((month % 2) == 1) ? 30 : 29);
}