∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Preadditive C] {X Y : C}
  {t : CategoryTheory.Limits.BinaryBicone X Y} (ht : CategoryTheory.Limits.IsColimit t.toCocone),
  t.fst = ht.desc (CategoryTheory.Limits.BinaryCofan.mk (CategoryTheory.CategoryStruct.id X) 0)