{ε α : Type} →
  (motive : Unit ⊕ Except ε (IO.AsyncList ε α) → Sort u_1) →
    (r : Unit ⊕ Except ε (IO.AsyncList ε α)) →
      ((val : Unit) → motive (Sum.inl val)) →
        ((tl : IO.AsyncList ε α) → motive (Sum.inr (Except.ok tl))) →
          ((e : ε) → motive (Sum.inr (Except.error e))) → motive r