let do_wp_proof server prover g =
let known_result prover (p,r) =
r=Wpo.Valid || (prover=p && p <> Wpo.Coqide)
in
if not (List.exists (known_result prover) (Wpo.get_results g))
then Task.spawn server
(Prover.prove ~callout:do_wpo_feedback g prover)