∀ {α : Type u_1} {β : Type u_2} {mα : MeasurableSpace α} {mβ : MeasurableSpace β} {s : Set β}
  (κ : ProbabilityTheory.Kernel α β) [ProbabilityTheory.IsFiniteKernel κ] (hs : MeasurableSet s),
  ProbabilityTheory.IsFiniteKernel (κ.restrict hs)