∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] [inst_1 : CategoryTheory.MonoidalCategory C] {D : Type u₂}
  [inst_2 : CategoryTheory.Category.{v₂, u₂} D] (e : C ≌ D) (X x x_1 : D) (f : x ⟶ x_1),
  CategoryTheory.MonoidalCategoryStruct.whiskerLeft X f =
    e.functor.map (CategoryTheory.MonoidalCategoryStruct.whiskerLeft (e.inverse.obj X) (e.inverse.map f))