∀ {α : Type u} {β : Type v} [inst : TopologicalSpace α] [inst_1 : LinearOrder α] [ClosedIciTopology α]
  [inst_3 : TopologicalSpace β] {a b : α} {f : α → β},
  a < b → ContinuousWithinAt f (Set.Ico a b) a = ContinuousWithinAt f (Set.Ici a) a