∀ {α : Type u} {β : α → Type v} {cmp : α → α → Ordering}
  {motive : (a : Lean.RBNode α β) → Lean.RBNode.WellFormed cmp a → Prop} {a : Lean.RBNode α β}
  (t : Lean.RBNode.WellFormed cmp a),
  motive Lean.RBNode.leaf ⋯ →
    (∀ {n n' : Lean.RBNode α β} {k : α} {v : β k} (a : Lean.RBNode.WellFormed cmp n)
        (a_1 : n' = Lean.RBNode.insert cmp n k v), motive n a → motive n' ⋯) →
      (∀ {n n' : Lean.RBNode α β} {k : α} (a : Lean.RBNode.WellFormed cmp n) (a_1 : n' = Lean.RBNode.erase cmp k n),
          motive n a → motive n' ⋯) →
        motive a t