∀ {α : Type u_1} (motive : (x : List α) → (x_1 : α) → x_1 ∈ x.getLast? → Prop) (x : List α) (x_1 : α)
  (x_2 : x_1 ∈ x.getLast?),
  (∀ (x : α) (hx : x ∈ [].getLast?), motive [] x hx) →
    (∀ (a x : α) (hx : x ∈ [a].getLast?), motive [a] x hx) →
      (∀ (a b : α) (l : List α) (x : α) (hx : x ∈ (a :: b :: l).getLast?), motive (a :: b :: l) x hx) → motive x x_1 x_2