∀ {C : Type u₁} {inst : CategoryTheory.Category.{v₁, u₁} C} {inst_1 : CategoryTheory.MonoidalCategory C} {D : Type u₂}
  {inst_2 : CategoryTheory.Category.{v₂, u₂} D} {inst_3 : CategoryTheory.MonoidalCategory D}
  (F : CategoryTheory.Functor C D) [self : F.Monoidal],
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Functor.LaxMonoidal.ε F)
      (CategoryTheory.Functor.OplaxMonoidal.η F) =
    CategoryTheory.CategoryStruct.id (CategoryTheory.MonoidalCategoryStruct.tensorUnit D)