∀ {α : Type u_1} {S : Stream'.WSeq (Computation α)} {a : α}
  (pe :
    Computation.parallel S =
      Computation.parallel
        (Stream'.WSeq.map (Computation.map fun c => c.1)
          (Stream'.WSeq.map (fun c => Computation.map (fun a => (a, c)) c) S)))
  (h' : a ∈ Computation.parallel S),
  (Computation.parallel (Stream'.WSeq.map (fun c => Computation.map (fun a => (a, c)) c) S)).get =
    (Computation.parallel (Stream'.WSeq.map (fun c => Computation.map (fun a => (a, c)) c) S)).get