∀ {𝒮 : Type u_6} [inst : CategoryTheory.Category.{u_5, u_6} 𝒮] (𝒳 : CategoryTheory.BasedCategory 𝒮)
  (𝒴 : CategoryTheory.BasedCategory 𝒮) (X : CategoryTheory.BasedFunctor 𝒳 𝒴),
  (CategoryTheory.CategoryStruct.id X).toNatTrans = CategoryTheory.CategoryStruct.id X.toFunctor