∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.MonoidalCategory C] {W X Y : C}
  (f : W ⟶ X) (g : X ⟶ Y) (Z : C) {Z_1 : C} (h : CategoryTheory.MonoidalCategoryStruct.tensorObj Y Z ⟶ Z_1),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerRight f Z)
      (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerRight g Z) h) =
    CategoryTheory.CategoryStruct.comp
      (CategoryTheory.MonoidalCategoryStruct.whiskerRight (CategoryTheory.CategoryStruct.comp f g) Z) h