proposition: Lemma mem_spec' {elt} x (m:t elt) : reflect (In x m) (mem x m).
proof: Proof. apply iff_reflect. apply mem_in_iff. Qed.
imports: Coq(Bool Equalities Orders OrdersFacts OrdersLists) Coq(Morphisms Permutation SetoidPermutation) MMaps(Utils Comparisons Interface)