include CSig.USetS with type elt = key
val mem : elt -> t -> bool
val remove : elt -> t -> t
val compare : t -> t -> int
val equal : t -> t -> bool
val subset : t -> t -> bool
val iter : (elt -> unit) -> t -> unit
val fold : (elt -> 'a -> 'a) -> t -> 'a -> 'a
val for_all : (elt -> bool) -> t -> bool
val exists : (elt -> bool) -> t -> bool
val filter : (elt -> bool) -> t -> t
val partition : (elt -> bool) -> t -> t * t
val elements : t -> elt list
val disjoint : t -> t -> bool
val min_elt_opt : t -> elt option
val max_elt_opt : t -> elt option
val choose_opt : t -> elt option
val split : elt -> t -> t * bool * t
val find_opt : elt -> t -> elt option
val find_first : (elt -> bool) -> t -> elt
val find_first_opt : (elt -> bool) -> t -> elt option
val find_last : (elt -> bool) -> t -> elt
val find_last_opt : (elt -> bool) -> t -> elt option
val of_list : elt list -> t
val to_seq_from : elt -> t -> elt Stdlib.Seq.t
val to_seq : t -> elt Stdlib.Seq.t
val add_seq : elt Stdlib.Seq.t -> t -> t
val of_seq : elt Stdlib.Seq.t -> t