∀ {α : Type u} {β : α → Type v} {instOrd : Ord α} {t : Std.DTreeMap.Internal.Impl α β} [Std.TransOrd α]
  [inst : Inhabited α],
  t.WF →
    t.isEmpty = false →
      ∀ {k : α} {v : β k}, (compare (Std.DTreeMap.Internal.Impl.insert! k v t).minKey! t.minKey!).isLE = true