∀ {C : Type u_4} [inst : CategoryTheory.Category.{u_3, u_4} C] {D : Type u_2}
  [inst_1 : CategoryTheory.Category.{u_1, u_2} D] {L : CategoryTheory.Functor C D} {R : CategoryTheory.Functor D C}
  (h : L ⊣ R) (X : C),
  CategoryTheory.CategoryStruct.comp (L.map (h.unit.app X)) (h.toComonad.ε.app (L.obj X)) =
    CategoryTheory.CategoryStruct.id (L.obj X)