`sig
type t = (int * int) BatAvlTree.tree
type elt = int
val empty : BatISet.t
val is_empty : BatISet.t -> bool
val mem : int -> BatISet.t -> bool
val add : int -> BatISet.t -> BatISet.t
val add_range : int -> int -> BatISet.t -> BatISet.t
val singleton : int -> BatISet.t
val remove : int -> BatISet.t -> BatISet.t
val remove_range : int -> int -> BatISet.t -> BatISet.t
val union : BatISet.t -> BatISet.t -> BatISet.t
val inter : BatISet.t -> BatISet.t -> BatISet.t
val diff : BatISet.t -> BatISet.t -> BatISet.t
val compl : BatISet.t -> BatISet.t
val compare : BatISet.t -> BatISet.t -> int
val equal : BatISet.t -> BatISet.t -> bool
val ord : BatISet.t -> BatISet.t -> BatOrd.order
val subset : BatISet.t -> BatISet.t -> bool
val from : int -> BatISet.t -> BatISet.t
val after : int -> BatISet.t -> BatISet.t
val until : int -> BatISet.t -> BatISet.t
val before : int -> BatISet.t -> BatISet.t
val iter : (int -> unit) -> BatISet.t -> unit
val iter_range : (int -> int -> unit) -> BatISet.t -> unit
val fold : (int -> 'a -> 'a) -> BatISet.t -> 'a -> 'a
val fold_range : (int -> int -> 'a -> 'a) -> BatISet.t -> 'a -> 'a
val for_all : (int -> bool) -> BatISet.t -> bool
val exists : (int -> bool) -> BatISet.t -> bool
val filter : (int -> bool) -> BatISet.t -> BatISet.t
val partition : (int -> bool) -> BatISet.t -> BatISet.t * BatISet.t
val cardinal : BatISet.t -> int
val elements : BatISet.t -> int list
val ranges : BatISet.t -> (int * int) list
val min_elt : BatISet.t -> int
val max_elt : BatISet.t -> int
val choose : BatISet.t -> int
val enum : BatISet.t -> (int * int) BatEnum.t
val of_enum : (int * int) BatEnum.t -> BatISet.t
val of_list : (int * int) list -> BatISet.t
val print : 'a BatIO.output -> BatISet.t -> unit
end`