type nonrec t = (module Hashmap)
type nonrec t = (module Hashmap with type key = string)
type nonrec t = (module Hashmap with type key = string and type value = int)
type nonrec toValueLikeInstance =
  'a t -> (module RxValueLikeInstance.S with type a = 'a) (a:1)
type nonrec 'a t = (module Test with type a = 'a)
type nonrec t = (module Console) ref
let (devices : (string, (module DEVICE)) Hastbl.t) = Hashtbl.creat 17