∀ {α : Type u_1} {β : Type u_2} {γ : Type u_3} {mα : MeasurableSpace α} {mβ : MeasurableSpace β}
  {mγ : MeasurableSpace γ} {a : α} {κ : ProbabilityTheory.Kernel α β} {η : ProbabilityTheory.Kernel β γ} {δ : Type u_5}
  [inst : TopologicalSpace δ] {f : γ → δ},
  MeasureTheory.AEStronglyMeasurable f ((η.comp κ) a) → ∀ᵐ (x : β) ∂κ a, MeasureTheory.AEStronglyMeasurable f (η x)