∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] {D : Type u_4}
  [inst_1 : CategoryTheory.Category.{u_3, u_4} D] (R : CategoryTheory.Functor D C) (L : CategoryTheory.Functor C D)
  (h : L ⊣ R) (x : C), Nonempty (x ⟶ R.obj (L.obj x))