fact: Definition indexed_cat_id_nat_z_iso {C : category} (Φ : indexed_cat C) (x : C) : nat_z_iso (functor_identity (Φ x)) (Φ $ identity x).
imports: UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations