`sig
type t
module V :
sig
type t
type label
val label : DGraphSubTree.G.V.t -> DGraphSubTree.G.V.label
val hash : DGraphSubTree.G.V.t -> int
val equal : DGraphSubTree.G.V.t -> DGraphSubTree.G.V.t -> bool
end
module E : sig type t end
val iter_succ :
(DGraphSubTree.G.V.t -> unit) ->
DGraphSubTree.G.t -> DGraphSubTree.G.V.t -> unit
val iter_pred :
(DGraphSubTree.G.V.t -> unit) ->
DGraphSubTree.G.t -> DGraphSubTree.G.V.t -> unit
val find_edge :
DGraphSubTree.G.t ->
DGraphSubTree.G.V.t -> DGraphSubTree.G.V.t -> DGraphSubTree.G.E.t
end`