A small c sharp function

I need a small c# function: private enum Frequency { Weekly = 2, // every week BiWeekly, // every two weeks Monthly, // every first week of the month FirstAndThirdWeeksOfMonth, // every 1st and 3rd weeks of the month SecondAndFourthWeeksOfMonth // every 2nd and 4th weeks of the month } private List<DateTime> CalculateSchedule(DateTime startDate, DateTime endDate, DateTime[] excludedDates, DayOfWeek[] daysOfWeek, Frequency frequency) { List<DateTime> result = new List<DateTime>(); // write function here return result; }