∀ {α : Type u_1} {cmp : α → α → Ordering} {v : α} {t : Batteries.RBNode α}
  (motive : (∃ L R, t.toList = L ++ R ∧ (Batteries.RBNode.insert cmp t v).toList = L ++ v :: R) → Prop)
  (x : ∃ L R, t.toList = L ++ R ∧ (Batteries.RBNode.insert cmp t v).toList = L ++ v :: R),
  (∀ (w w_1 : List α) (left : t.toList = w ++ w_1) (h : (Batteries.RBNode.insert cmp t v).toList = w ++ v :: w_1),
      motive ⋯) →
    motive x