∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] {X : ℕ → C} (f : (n : ℕ) → X n ⟶ X (n + 1)) (i : ℕ),
  CategoryTheory.Functor.OfSequence.map f i i ⋯ = CategoryTheory.CategoryStruct.id (X i)