∀ {X : Type u_1} {ε : Type u_3} [inst : MeasurableSpace X] [inst_1 : TopologicalSpace X] [inst_2 : TopologicalSpace ε]
  [inst_3 : ContinuousENorm ε] {f : X → ε} {μ : MeasureTheory.Measure X} [SecondCountableTopology X],
  MeasureTheory.LocallyIntegrable f μ →
    ∃ u, (∀ (n : ℕ), IsOpen (u n)) ∧ ⋃ n, u n = Set.univ ∧ ∀ (n : ℕ), MeasureTheory.IntegrableOn f (u n) μ