K2.Makemodule H1 : Hashtbl.HashedTypemodule H2 : Hashtbl.HashedTypeval create : int -> 'a tval clear : 'a t -> unitval reset : 'a t -> unitval length : 'a t -> intval stats : 'a t -> Hashtbl.statisticsval clean : 'a t -> unitval stats_alive : 'a t -> Hashtbl.statistics