(** ** makeBlack, MakeRed *)

(* Specifications: *)
Lemma makeBlack_spec s x : InT x (makeBlack s) <-> InT x s.
Lemma makeRed_spec s x : InT x (makeRed s) <-> InT x s.
#[global]
Instance makeBlack_ok s `{Ok s} : Ok (makeBlack s).