∀ {α : Type u_1} {β : Type u_2} [inst : MeasurableSpace α] [inst_1 : MeasurableSpace β] [inst_2 : SizeOf α]
  [inst_3 : SizeOf β] (toFun : α → MeasureTheory.Measure β) (measurable' : Measurable toFun),
  sizeOf { toFun := toFun, measurable' := measurable' } = 1