∀ {C : Type u_1} [inst : CategoryTheory.Category.{u_4, u_1} C] {R : CategoryTheory.Functor Cᵒᵖ RingCat}
  {M₁ M₂ : PresheafOfModules R} (app : (X : Cᵒᵖ) → M₁.obj X ≅ M₂.obj X)
  (naturality :
    ∀ ⦃X Y : Cᵒᵖ⦄ (f : X ⟶ Y),
      CategoryTheory.CategoryStruct.comp (M₁.map f)
          ((ModuleCat.restrictScalars (RingCat.Hom.hom (R.map f))).map (app Y).hom) =
        CategoryTheory.CategoryStruct.comp (app X).hom (M₂.map f)),
  CategoryTheory.CategoryStruct.comp { app := fun X => (app X).inv, naturality := ⋯ }
      { app := fun X => (app X).hom, naturality := ⋯ } =
    CategoryTheory.CategoryStruct.id M₂