∀ {J : Type w} [inst : CategoryTheory.Category.{v, w} J] (F : CategoryTheory.Functor J AlgebraicGeometry.Scheme)
  [inst_1 : ∀ {i j : J} (f : i ⟶ j), AlgebraicGeometry.IsOpenImmersion (F.map f)]
  [inst_2 : (F.comp AlgebraicGeometry.Scheme.forget).IsLocallyDirected] [inst_3 : Quiver.IsThin J]
  [inst_4 : Small.{u, w} J], (AlgebraicGeometry.Scheme.IsLocallyDirected.openCover F).I₀ = J