∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  (e : C ≌ D) {G : CategoryTheory.Functor D C} (iso : e.inverse ≅ G) (X : C),
  (e.changeInverse iso).unitIso.hom.app X =
    CategoryTheory.CategoryStruct.comp (e.unitIso.hom.app X) (iso.hom.app (e.functor.obj X))