Examples:

The following is true Monday through Friday (local time zone). weekdayRange("MON", "FRI")

The following is true Monday through Friday, in Greenwich Mean Time. weekdayRange("MON", "FRI", "GMT")

The following is true on Saturdays, local time.weekdayRange("SAT")

The following is true on Saturdays, in Greenwich Mean Time.weekdayRange("SAT", "GMT")

The following is true Friday through Monday (the order is important)weekdayRange("FRI", "MON")