∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  (X Y : C) [inst_2 : CategoryTheory.Limits.HasBinaryBiproduct X Y] {b : CategoryTheory.Limits.BinaryBicone X Y}
  (hb : b.IsBilimit),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.biprod.lift b.fst b.snd)
      (CategoryTheory.Limits.biprod.desc b.inl b.inr) =
    CategoryTheory.CategoryStruct.id b.pt