let create
    ?(host=Host.tmp_on_localhost)
    ?queue ?name ?(wall_limit=`Hours 24.) ?(processors=1) ?(email_user=`Never
    ?(shell="/usr/bin/env bash")
    program =
  `Long_running (
    "PBS",
    `Created {host; program; queue; name; 
              email_user; shell; wall_limit; processors}
    |> serialize)