∀ {X : Type u_6} {f : X → ℝ} {m m0 : MeasurableSpace X} {μ : MeasureTheory.Measure X},
  m ≤ m0 → ∀ (g : MeasureTheory.SimpleFunc X ℝ), MeasureTheory.Integrable f μ → MeasureTheory.Integrable (⇑g * f) μ