∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z)
  [inst_1 : CategoryTheory.IsIso g],
  (CategoryTheory.Limits.pullbackConeOfRightIso f g).snd = CategoryTheory.CategoryStruct.comp f (CategoryTheory.inv g)