∀ {α : Type u_1} {β : Type u_2} {f f_1 : α → β} (e_f : f = f_1) [inst : TopologicalSpace β] {x : MeasurableSpace α}
  (hf : MeasureTheory.StronglyMeasurable f) (a a_1 : ℕ), a = a_1 → hf.approx a = ⋯.approx a_1