∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {H : Type u_2} [inst_1 : TopologicalSpace H] {E : Type u_3}
  [inst_2 : NormedAddCommGroup E] [inst_3 : NormedSpace 𝕜 E] {I : ModelWithCorners 𝕜 E H} {G : Type u_4}
  [inst_4 : Add G] [inst_5 : TopologicalSpace G] [inst_6 : ChartedSpace H G] [ContMDiffAdd I 1 G] {a b : G},
  MDifferentiableAt I I (fun x => a + x) b