∀ {𝕜 : Type u} [inst : NontriviallyNormedField 𝕜] {F : Type v} [inst_1 : NormedAddCommGroup F]
  [inst_2 : NormedSpace 𝕜 F] {f : 𝕜 → F} {x₀ : 𝕜} {C : ℝ},
  0 ≤ C → (∀ᶠ (x : 𝕜) in nhds x₀, ‖f x - f x₀‖ ≤ C * ‖x - x₀‖) → ‖deriv f x₀‖ ≤ C