{α : Type u} →
  {β : Type v} →
    {cmp : α → α → Ordering} →
      {motive : Std.TreeMap α β cmp → Sort u_1} →
        ((inner : Std.DTreeMap α (fun x => β) cmp) → motive { inner := inner }) → (t : Std.TreeMap α β cmp) → motive t