sig val ( /> ) : ('a, 'b) Hashtbl.t -> 'a -> 'b val ( /+ ) : ('a, 'b) Hashtbl.t -> ('a, 'b) Hashtbl.t -> ('a, 'b) Hashtbl.t val ( // ) : ('a, 'b) Hashtbl.t -> 'a * 'b -> ('a, 'b) Hashtbl.t end