∀ {𝕜 : Type u} [inst : NontriviallyNormedField 𝕜] {E : Type uE} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {F : Type uF} [inst_3 : NormedAddCommGroup F] [inst_4 : NormedSpace 𝕜 F] {f : E → F}
  {s : Set E} {n : ℕ},
  fderivWithin 𝕜 (iteratedFDerivWithin 𝕜 n f s) s =
    ⇑(continuousMultilinearCurryLeftEquiv 𝕜 (fun x => E) F) ∘ iteratedFDerivWithin 𝕜 (n + 1) f s