∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {D : Type u'} [inst_1 : CategoryTheory.Category.{v', u'} D]
  (K L : CategoryTheory.Functor C D) (X : C) (f : L ⟶ L)
  (x :
    CategoryTheory.MonoidalCategoryStruct.tensorObj ((K.functorHom L).obj X)
      (CategoryTheory.MonoidalCategoryStruct.tensorUnit (Type (max (max u v) v')))),
  (CategoryTheory.MonoidalCategoryStruct.whiskerLeft (K.functorHom L) (CategoryTheory.Functor.natTransEquiv.symm f)).app
      X x =
    (x.1, CategoryTheory.Functor.HomObj.ofNatTrans f)