∀ {M : Type u_2} {ι : Type u_3} {α : Type u_4} [inst : AddCommMonoid M] [inst_1 : MeasurableSpace M] [MeasurableAdd₂ M]
  {m : MeasurableSpace α} {μ : MeasureTheory.Measure α} {f : ι → α → M} (s : Finset ι),
  (∀ i ∈ s, AEMeasurable (f i) μ) → AEMeasurable (fun a => ∑ i ∈ s, f i a) μ