∀ {α : Type u} {β : α → Type v} [inst : Ord α] {sz : ℕ} {k : α} {v : β k} {l r : Std.DTreeMap.Internal.Impl α β},
  (Std.DTreeMap.Internal.Impl.inner sz k v l r).Ordered →
    ∀ {k' : (a : α) × β a}, k' ∈ r.toListModel → compare k k'.fst = Ordering.lt