fact: Definition expand_list {A} (default : A) (ls : list A) (n : nat) : list A := expand_list_helper default ls n 0.
imports: Coq.ZArith.ZArith Coq.Lists.List Coq.Setoids.Setoid Coq.Classes.Morphisms Coq.QArith.QArith_base Coq.QArith.Qreduction Coq.QArith.Qround