proposition: Lemma get_string_of_list str n : String.get n (string_of_list str) = List.nth_error str n.
proof: Proof. revert n; induction str as [|ch str IHstr]; intros; destruct n as [|n]; simpl in *; auto. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Coq.Arith.PeanoNat Coq.Strings.Ascii Coq.Strings.String Fiat.Common.List.Operations Fiat.Common.StringOperations