Extended version of OCaml's maps
module type MonadS = sig ... endmodule type S = Stdlib.Map.Smodule type UExtS = sig ... endmodule type ExtS = sig ... endmodule Make (M : Stdlib.Map.OrderedType) : ExtS with type key = M.t and type
'a t = 'a Stdlib.Map.Make(M).t and module Set := Stdlib.Set.Make(M)