∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C]
  {X Y : CategoryTheory.Functor (CategoryTheory.Discrete PUnit.{w + 1}) C} (θ : X ⟶ Y),
  CategoryTheory.Functor.equiv.functor.map θ = θ.app { as := PUnit.unit }