∀ {α : Type u_8} {ι : Type u_9} [inst : Preorder ι] [Filter.atTop.IsCountablyGenerated] {x : MeasurableSpace α}
  {μ : MeasureTheory.Measure α} {f : ι → Set α},
  Filter.Tendsto (fun i => μ (Set.accumulate f i)) Filter.atTop (nhds (μ (⋃ i, f i)))