val vertex_properties : (string * string * string option) list
List of the type of the vertex proprierties.
The format is (id,type,default).
val edge_properties : (string * string * string option) list
List of the type of the edge proprierties.
val map_vertex : Graphml.G.vertex -> (string * string) list
Associates to each vertex a key/value list where
the key is the id of a vertex attribute and the value is the value
associated to this vertex
val map_edge : Graphml.G.E.t -> (string * string) list
Associates to each edge a key/value list
val vertex_uid : Graphml.G.vertex -> int
Returns a unique integer identifier for the vertex
val edge_uid : Graphml.G.E.t -> int
Returns a unique integer identifier for the edge