module ListMenv : MENV = struct

  type 'a menv = (string * 'a) list 

  let empty = [] (* replace this stub *)

  let bind name valu env = raise (Failure "unimplemented") (* replace this stub *)

  let make names values = raise (Failure "unimplemented") (* replace this stub *)

  let lookup name env = raise (Failure "unimplemented") (* replace this stub *)

  let merge env1 env2 = raise (Failure "unimplemented") (* replace this stub *)

end