∀ {α : Type u_1} {c₀ : Batteries.RBColor} {n₀ : ℕ} {c : Batteries.RBColor} {n : ℕ} {t : Batteries.RBNode α}
  {path : Batteries.RBNode.Path α},
  Batteries.RBNode.Path.Balanced c₀ n₀ path c n →
    Batteries.RBNode.RedRed (c = Batteries.RBColor.red) t n → ∃ n, (path.ins t).Balanced Batteries.RBColor.black n