module Kn: sig .. end
type ('k, 'd) t 
an ephemeron with an arbitrary number of keys
                      of the same type
val create : int -> ('k, 'd) t
val get_key : ('k, 'd) t -> int -> 'k option
val get_key_copy : ('k, 'd) t -> int -> 'k option
val set_key : ('k, 'd) t -> int -> 'k -> unit
val unset_key : ('k, 'd) t -> int -> unit
val check_key : ('k, 'd) t -> int -> bool
val blit_key : ('k, 'a) t ->
       int -> ('k, 'b) t -> int -> int -> unit
val get_data : ('k, 'd) t -> 'd option
val get_data_copy : ('k, 'd) t -> 'd option
val set_data : ('k, 'd) t -> 'd -> unit
val unset_data : ('k, 'd) t -> unit
val check_data : ('k, 'd) t -> bool
val blit_data : ('k, 'd) t -> ('k, 'd) t -> unit
module Make: 
Functor building an implementation of a weak hash table
module MakeSeeded: 
Functor building an implementation of a weak hash table.