∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C]
  [inst_2 : CategoryTheory.Limits.HasFiniteBiproducts C] {J : Type} [inst_3 : Finite J]
  (F : J → CategoryTheory.Idempotents.Karoubi C),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.biproduct.map fun j => (F j).p)
      (CategoryTheory.Limits.biproduct.map fun j => (F j).p) =
    CategoryTheory.Limits.biproduct.map fun j => (F j).p