∀ {C : Type u_4} [inst : CategoryTheory.Category.{u_3, u_4} C] {D : Type u_2}
  [inst_1 : CategoryTheory.Category.{u_1, u_2} D] [inst_2 : CategoryTheory.MonoidalCategory D]
  (A : CategoryTheory.Functor C D) [inst_3 : CategoryTheory.MonObj A] (X : C),
  (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerLeft A CategoryTheory.MonObj.one)
          CategoryTheory.MonObj.mul).app
      X =
    (CategoryTheory.MonoidalCategoryStruct.rightUnitor A).hom.app X