module GraphmlPrinter:Graph.Graphml.Print(G)(sigval vertex_properties :(string * string * 'a option) listval edge_properties :(string * string * 'a option) listval map_edge :'a -> 'b listval map_vertex :Cudf.package -> (string * string) listval edge_uid :'a -> intval vertex_uid :'a -> intend)