∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.MonoidalCategory C] {X Y : C}
  (f : X ⟶ Y) (X' : C),
  CategoryTheory.CategoryStruct.comp
      (CategoryTheory.MonoidalCategoryStruct.whiskerRight ((CategoryTheory.Functor.id C).map f)
        ((CategoryTheory.Functor.id C).obj X'))
      (CategoryTheory.CategoryStruct.id
        (CategoryTheory.MonoidalCategoryStruct.tensorObj ((CategoryTheory.Functor.id C).obj Y)
          ((CategoryTheory.Functor.id C).obj X'))) =
    CategoryTheory.CategoryStruct.comp
      (CategoryTheory.CategoryStruct.id
        (CategoryTheory.MonoidalCategoryStruct.tensorObj ((CategoryTheory.Functor.id C).obj X)
          ((CategoryTheory.Functor.id C).obj X')))
      ((CategoryTheory.Functor.id C).map (CategoryTheory.MonoidalCategoryStruct.whiskerRight f X'))