String label;
String edgeSymbol;
if (transit.size() == 0 || transit.get(0).isDirected()) {
if (completeOutput) println("Directed graph.");
gv.addln(gv.startDigraph());
edgeSymbol = GraphViz.edgeSymbolDirected;
} else {
if (completeOutput) println("Undirected graph.");
gv.addln(gv.startGraph());
edgeSymbol = GraphViz.edgeSymbolUnDirected;