∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.MonoidalCategory C] {X Y Y' : C}
  [inst_2 : CategoryTheory.ExactPairing X Y'] (i : Y ≅ Y'),
  CategoryTheory.CategoryStruct.comp
      (CategoryTheory.MonoidalCategoryStruct.whiskerRight
        (CategoryTheory.CategoryStruct.comp (η_ X Y') (CategoryTheory.MonoidalCategoryStruct.whiskerLeft X i.inv)) X)
      (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.associator X Y X).hom
        (CategoryTheory.MonoidalCategoryStruct.whiskerLeft X
          (CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerRight i.hom X)
            (ε_ X Y')))) =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.leftUnitor X).hom
      (CategoryTheory.MonoidalCategoryStruct.rightUnitor X).inv