∀ {C : Type u_1} {D : Type u_2} [inst : CategoryTheory.Category.{v_1, u_1} C]
  [inst_1 : CategoryTheory.Category.{v_2, u_2} D] (L : CategoryTheory.Functor C D) {H : Type u_3}
  [inst_2 : CategoryTheory.Category.{v_3, u_3} H] [inst_3 : ∀ (F : CategoryTheory.Functor C H), L.HasLeftKanExtension F]
  (G : CategoryTheory.Functor D H) {Z : CategoryTheory.Functor C H} (h : L.comp G ⟶ Z),
  CategoryTheory.CategoryStruct.comp (L.lanUnit.app (L.comp G))
      (CategoryTheory.CategoryStruct.comp (L.whiskerLeft ((L.lanAdjunction H).counit.app G)) h) =
    h