∀ {C : Type u_1} [inst : CategoryTheory.Category.{u_4, u_1} C] {D : Type u_3}
  [inst_1 : CategoryTheory.Category.{u_2, u_3} D] [inst_2 : CategoryTheory.MonoidalCategory D]
  (F : CategoryTheory.Functor C (CategoryTheory.Mon D)),
  CategoryTheory.CategoryStruct.comp
      (CategoryTheory.MonoidalCategoryStruct.whiskerLeft (F.comp (CategoryTheory.Mon.forget D))
        { app := fun X => CategoryTheory.MonObj.one, naturality := ⋯ })
      { app := fun X => CategoryTheory.MonObj.mul, naturality := ⋯ } =
    (CategoryTheory.MonoidalCategoryStruct.rightUnitor (F.comp (CategoryTheory.Mon.forget D))).hom