refine'
  (hf.differentiable_on_iterated_deriv_within _ (uniqueDiffOn_Icc hab)).mono Ioo_subset_Icc_self
f : ℝ → ℝ
a b C x x₀ : ℝ
n : ℕ
hab✝ : a ≤ b
hf : ContDiffOn ℝ (↑n + 1) f (Icc a b)
hx : x ∈ Icc a b
hx₀ : x₀ ∈ Icc a b
hC : ∀ y ∈ Ioo a b, ‖iteratedDerivWithin (n + 1) f (Icc a b) y‖ ≤ C
hab : a < b
⊢ DifferentiableOn ℝ (iteratedDerivWithin n f (Icc a b)) (Ioo a b)
no goals