∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Limits.HasFiniteProducts C]
  {X Y : CategoryTheory.Limits.FormalCoproduct C} (f : X ⟶ Y) (x : SimplexCategoryᵒᵖ),
  (CategoryTheory.Limits.FormalCoproduct.cechFunctor.map f).app x =
    CategoryTheory.Limits.FormalCoproduct.powerMap f (CategoryTheory.ToType (Opposite.unop x))