∀ {α : Type u_1} {E : Type u_2} {m : MeasurableSpace α} {p : ENNReal} {μ : MeasureTheory.Measure α}
  [inst : NormedAddCommGroup E] {β : Type u_3} [inst_1 : MeasurableSpace β] {μb : MeasureTheory.Measure β}
  (𝕜 : Type u_4) [inst_2 : NormedRing 𝕜] [inst_3 : Module 𝕜 E] [inst_4 : IsBoundedSMul 𝕜 E] (f : α → β)
  (hf : MeasureTheory.MeasurePreserving f μ μb) (c : 𝕜) (g : ↥(MeasureTheory.Lp E p μb)),
  (↑(MeasureTheory.Lp.compMeasurePreserving f hf)).toFun (c • g) =
    (RingHom.id 𝕜) c • (↑(MeasureTheory.Lp.compMeasurePreserving f hf)).toFun g