∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {E : Type u_2} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {E' : Type u_5} [inst_3 : NormedAddCommGroup E'] [inst_4 : NormedSpace 𝕜 E']
  {n : WithTop ℕ∞} {f : E → E'} {x : E},
  ContMDiffAt (modelWithCornersSelf 𝕜 E) (modelWithCornersSelf 𝕜 E') n f x → ContDiffAt 𝕜 n f x