`sig type key type 'a t val create : ?random:bool -> int -> 'a t val clear : 'a t -> unit val reset : 'a t -> unit val copy : 'a t -> 'a t val add : 'a t -> key -> 'a -> unit val remove : 'a t -> key -> unit val find : 'a t -> key -> 'a val find_all : 'a t -> key -> 'a list val replace : 'a t -> key -> 'a -> unit val mem : 'a t -> key -> bool val iter : (key -> 'a -> unit) -> 'a t -> unit val filter_map_inplace : (key -> 'a -> 'a option) -> 'a t -> unit val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b val length : 'a t -> int val stats : 'a t -> Hashtbl.statistics val clean : 'a t -> unit val stats_alive : 'a t -> Hashtbl.statistics end`