proposition: Lemma add_1 m x y e : K.eq x y -> MapsTo y e (add x e m).
proof: Proof. intros <-. rewrite <-find_spec. apply add_spec1. Qed.
imports: Coq(Bool Equalities Orders OrdersFacts OrdersLists) Coq(Morphisms Permutation SetoidPermutation) MMaps(Utils Comparisons Interface)