module Make(Th: Theory_intf)() : sig
  type 'f sat_state = { eval : 'f -> bool; ... }
  type ('c,'p) unsat_state =
    { conflict: unit -> 'c; proof : unit -> 'p }
  type res = Sat of formula sat_state
           | Unsat of (clause, proof) unsat_state
  val assume : ?tag:int -> atom list list -> unit
  val solve : ?assumptions:atom list -> unit -> res
end