∀ {α : Type u_1} {β : Type u_2} {γ : Type u_3} [inst : TopologicalSpace α] [inst_1 : TopologicalSpace β]
  [inst_2 : TopologicalSpace γ] {g : β → γ} {f : α → β} {s : Set α},
  Continuous g → ContinuousOn f s → ContinuousOn (g ∘ f) s