fact: Definition z_iso_to_inv2cell {a b : B} {f g : hom a b} (α : z_iso f g) : invertible_2cell f g.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.Bicategories.Core.Bicat