fact: Definition invertible_2cell_to_nat_z_iso {C D : bicat_of_cats} (F G : C --> D) : invertible_2cell F G → nat_z_iso F G.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.whiskering UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.HorizontalComposition UniMath.CategoryTheory.PrecategoryBinProduct UniMath.Bicategories.Core.Bicat