∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] {X Y : C} {c : CategoryTheory.Limits.BinaryCofan X Y}
  (hc : CategoryTheory.Limits.IsColimit c) (s : CategoryTheory.Limits.BinaryFan (Opposite.op X) (Opposite.op Y))
  (m :
    s.pt ⟶
      Opposite.op
        (((CategoryTheory.Functor.const (CategoryTheory.Discrete CategoryTheory.Limits.WalkingPair)).obj c.pt).obj
          { as := CategoryTheory.Limits.WalkingPair.left })),
  CategoryTheory.CategoryStruct.comp m c.inr.op = s.snd →
    CategoryTheory.CategoryStruct.comp c.inr m.unop =
      CategoryTheory.CategoryStruct.comp c.inr ((fun s => (hc.desc s.unop).op) s).unop