∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C] {X Y : C}
  {t : CategoryTheory.Limits.Cocone (CategoryTheory.Limits.pair X Y)} (ht : CategoryTheory.Limits.IsColimit t),
  CategoryTheory.CategoryStruct.comp (t.ι.app { as := CategoryTheory.Limits.WalkingPair.left })
      (ht.desc (CategoryTheory.Limits.BinaryCofan.mk 0 (CategoryTheory.CategoryStruct.id Y))) =
    0