∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] {D : Type u_2}
  [inst_1 : CategoryTheory.Category.{v_2, u_2} D] [inst_2 : CategoryTheory.MonoidalCategory D]
  (F : CategoryTheory.Functor C D) (X : C),
  (CategoryTheory.Functor.LaxMonoidal.ofBifunctor.leftMapₗ F).app X =
    (CategoryTheory.MonoidalCategoryStruct.leftUnitor (F.obj X)).hom