* @returns two list, the first contains at least n elements, the second the
* remaining ones
* @raise Failure when List.length l < n *)
-(* FG: first argument: error msg *)
-val split_nth: string -> int -> 'a list -> 'a list * 'a list
+val split_nth: int -> 'a list -> 'a list * 'a list
(** skip [n] [l] skips the first n elements of l *)
val list_skip : int -> 'a list -> 'a list