let set = try Hashtbl.find by_rank r with Not_found -> StateSet.empty in
Hashtbl.replace by_rank r (StateSet.union s set)) !rank_list;
auto.ranked_states <-
let set = try Hashtbl.find by_rank r with Not_found -> StateSet.empty in
Hashtbl.replace by_rank r (StateSet.union s set)) !rank_list;
auto.ranked_states <-