Calendar.RecurrenceRule.Weekday.nth(_:_:)
Repeat on the n-th instance of the specified weekday in a month, if the recurrence has a monthly frequency. If the recurrence has a yearly frequency, repeat on the n-th week of the year.
Declaration
case nth(Int, Locale.Weekday)Discussion
If n is negative, repeat on the n-to-last of the given weekday.