val iter : t -> (elt -> unit) -> unit
val fold : t -> 'a -> (elt -> 'a -> 'a) -> 'a
val for_all : t -> (elt -> bool) -> bool
val exists : t -> (elt -> bool) -> bool
val elements : t -> elt list
val mem : t -> elt -> bool
val remove : t -> elt -> t
val of_list : elt list -> t
val of_sorted_array : elt array -> t
val invariant : t -> bool
val print : Stdlib.Format.formatter -> t -> unit