proposition: Lemma NOABT_singleton_inr_nil : forall A h, @no_output_at_backup_trace A [(h, inr [])].
proof: Proof. Proof using. unfold no_output_at_backup_trace, no_output_at_backup. simpl. intros. intuition. subst. simpl in *. find_inversion. auto. Qed.
imports: Verdi(Verdi HandlerMonad)