∀ {α : Type u} {β : α → Type v} (impl : Std.DTreeMap.Internal.Impl α β) (balanced_impl : impl.Balanced)
  (impl_1 : Std.DTreeMap.Internal.Impl α β) (balanced_impl_1 : impl_1.Balanced),
  ({ impl := impl, balanced_impl := balanced_impl } = { impl := impl_1, balanced_impl := balanced_impl_1 }) =
    (impl = impl_1)