∀ {Ω : Type u_1} {ι : Type u_2} {m : MeasurableSpace Ω} {β : ι → Type u_3} [inst : (i : ι) → TopologicalSpace (β i)]
  [inst_1 : ∀ (i : ι), TopologicalSpace.MetrizableSpace (β i)] [mβ : (i : ι) → MeasurableSpace (β i)]
  [inst_2 : ∀ (i : ι), BorelSpace (β i)] [inst_3 : Preorder ι] [inst_4 : (i : ι) → MulZeroOneClass (β i)]
  [∀ (i : ι), Nontrivial (β i)] {s : ι → Set Ω} (hsm : ∀ (i : ι), MeasurableSet (s i)),
  MeasureTheory.filtrationOfSet hsm = MeasureTheory.Filtration.natural (fun i => (s i).indicator fun x => 1) ⋯