I need to define custom calendars and, in particular, test a DateTime for being a holiday. My current code is shown below. Is there a more concise/better way of doing this, preferably without sacrificing performance?let private isHoliday2011 (dt:DateTime) =  match dt.DayOfWeek with  | DayOfWeek.Saturday | DayOfWeek.Sunday ->    match (dt.Month, dt.Day) with    | (3,5) -> false    | _ -> true  | _ ->    match dt.Month with    | 1 ->      match dt.Day with      | 3 | 4 | 5 | 6 | 7 | 10 -> true      | _ -> false    | 2 ->      match dt.Day with      | 23 -> true      | _ -> false    | 3 ->      match dt.Day with      | 7 | 8 -> true      | _ -> false    | 5 ->      match dt.Day with      | 2 | 9 -> true      | _ -> false    | 6 ->      match dt.Day with      | 13 -> true      | _ -> false    | 11 ->      match dt.Day with      | 4 -> true      | _ -> false    | _ -> false
Is there a better way of defining custom calendars?
algorithm;f#