∀ {C : Type uC} [inst : CategoryTheory.Category.{uC', uC} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  [inst_2 : CategoryTheory.Limits.HasBinaryBiproducts C] (P Q : C),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.biprod.braiding P Q).hom
      (CategoryTheory.Limits.biprod.braiding Q P).hom =
    CategoryTheory.CategoryStruct.id (P ⊞ Q)