type t = Graph.Persistent.Digraph.ConcreteBidirectional(Node).t
val out_degree : t -> vertex -> int
val mem_vertex : t -> vertex -> bool
val mem_edge_e : t -> edge -> bool
val iter_vertex : ( vertex -> unit ) -> t -> unit
val fold_vertex : ( vertex -> 'a -> 'a ) -> t -> 'a -> 'a
val fold_edges : ( vertex -> vertex -> 'a -> 'a ) -> t -> 'a -> 'a
val iter_edges_e : ( edge -> unit ) -> t -> unit
val fold_edges_e : ( edge -> 'a -> 'a ) -> t -> 'a -> 'a
val fold_succ : ( vertex -> 'a -> 'a ) -> t -> vertex -> 'a -> 'a
val fold_pred : ( vertex -> 'a -> 'a ) -> t -> vertex -> 'a -> 'a
val iter_succ_e : ( edge -> unit ) -> t -> vertex -> unit
val fold_succ_e : ( edge -> 'a -> 'a ) -> t -> vertex -> 'a -> 'a
val iter_pred_e : ( edge -> unit ) -> t -> vertex -> unit
val fold_pred_e : ( edge -> 'a -> 'a ) -> t -> vertex -> 'a -> 'a
val add_edge_e : t -> edge -> t
val remove_edge_e : t -> edge -> t