{α : Type u_1} →
  {β : α → Type u_2} →
    [inst : Ord α] →
      (motive : Std.DTreeMap.Internal.RxoIterator α β → Sort u_3) →
        (x : Std.DTreeMap.Internal.RxoIterator α β) →
          ((upper : α) → motive { iter := Std.DTreeMap.Internal.Zipper.done, upper := upper }) →
            ((k : α) →
                (v : β k) →
                  (t : Std.DTreeMap.Internal.Impl α β) →
                    (it : Std.DTreeMap.Internal.Zipper α β) →
                      (upper : α) → motive { iter := Std.DTreeMap.Internal.Zipper.cons k v t it, upper := upper }) →
              motive x