∀ {C : Type u_1} {H : Type u_3} {D : Type u_6} [inst : CategoryTheory.Category.{u_4, u_1} C]
  [inst_1 : CategoryTheory.Category.{u_2, u_3} H] [inst_2 : CategoryTheory.Category.{u_5, u_6} D]
  (F' : CategoryTheory.Functor D H) {L : CategoryTheory.Functor C D} {F : CategoryTheory.Functor C H}
  (α : F ⟶ L.comp F') [inst_3 : F'.IsLeftKanExtension α] {G : CategoryTheory.Functor C H} (i : F ≅ G)
  (G' : CategoryTheory.Functor D H) (β : G ⟶ L.comp G') [inst_4 : G'.IsLeftKanExtension β],
  CategoryTheory.CategoryStruct.comp β
      (L.whiskerLeft
        (CategoryTheory.CategoryStruct.comp
          (G'.descOfIsLeftKanExtension β F' (CategoryTheory.CategoryStruct.comp i.inv α))
          (F'.descOfIsLeftKanExtension α G' (CategoryTheory.CategoryStruct.comp i.hom β)))) =
    CategoryTheory.CategoryStruct.comp β (L.whiskerLeft (CategoryTheory.CategoryStruct.id G'))