{C : Type u} →
  [inst : CategoryTheory.Category.{v, u} C] →
    {motive : CategoryTheory.IsSifted C → Sort u_1} →
      (t : CategoryTheory.IsSifted C) →
        ([toFinal : (CategoryTheory.Functor.diag C).Final] → [nonempty : Nonempty C] → motive ⋯) → motive t