    sig
      type key
      and 'a t
      val create : int -> 'a MoreLabels.Hashtbl.S.t
      val clear : 'a MoreLabels.Hashtbl.S.t -> unit
      val copy : 'a MoreLabels.Hashtbl.S.t -> 'a MoreLabels.Hashtbl.S.t
      val add :
        'a MoreLabels.Hashtbl.S.t ->
        key:MoreLabels.Hashtbl.S.key -> data:'a -> unit
      val remove : 'a MoreLabels.Hashtbl.S.t -> MoreLabels.Hashtbl.S.key -> unit
      val find : 'a MoreLabels.Hashtbl.S.t -> MoreLabels.Hashtbl.S.key -> 'a
      val find_all :
        'a MoreLabels.Hashtbl.S.t -> MoreLabels.Hashtbl.S.key -> 'a list
      val replace :
        'a MoreLabels.Hashtbl.S.t ->
        key:MoreLabels.Hashtbl.S.key -> data:'a -> unit
      val mem : 'a MoreLabels.Hashtbl.S.t -> MoreLabels.Hashtbl.S.key -> bool
      val iter :
        f:(key:MoreLabels.Hashtbl.S.key -> data:'a -> unit) ->
        'a MoreLabels.Hashtbl.S.t -> unit
      val fold :
        f:(key:MoreLabels.Hashtbl.S.key -> data:'a -> 'b -> 'b) ->
        'a MoreLabels.Hashtbl.S.t -> init:'b -> 'b
    end