∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {W X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z}
  [inst_1 : CategoryTheory.Limits.HasPushout f g] (h : Y ⟶ W) (k : Z ⟶ W)
  (w : CategoryTheory.CategoryStruct.comp f h = CategoryTheory.CategoryStruct.comp g k),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.pushout.inr f g)
      (CategoryTheory.Limits.pushout.desc h k w) =
    k