`sig
val iter :
?pre:(Sig_pack.S.V.t -> unit) ->
?post:(Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> unit
val prefix : (Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> unit
val postfix : (Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> unit
val iter_component :
?pre:(Sig_pack.S.V.t -> unit) ->
?post:(Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> Sig_pack.S.V.t -> unit
val prefix_component :
(Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> Sig_pack.S.V.t -> unit
val postfix_component :
(Sig_pack.S.V.t -> unit) -> Sig_pack.S.t -> Sig_pack.S.V.t -> unit
val has_cycle : Sig_pack.S.t -> bool
end`