∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  (F : CategoryTheory.Functor C D) (d : D) (X : (CategoryTheory.CostructuredArrow F.op (Opposite.op d))ᵒᵖ),
  (CategoryTheory.CostructuredArrow.toStructuredArrow' F d).obj X =
    CategoryTheory.StructuredArrow.mk (Opposite.unop X).hom.unop