Date.Ymdexception Error_exn of errorConstructs a date in the Gregorian calendar.
Returns Error `Invalid_year if year < 0 || 9999 < year.
Returns Error `Invalid_month if month < 1 || 12 < month.
Returns Error `Invalid_day if day < 1 || day count of month < day.
val make_exn : year:int -> month:int -> day:int -> tval pp_iso8601 : Stdlib.Format.formatter -> t -> unitval to_iso8601 : t -> stringval of_iso8601 : string -> (t, string) Stdlib.resultval of_iso8601_exn : string -> t