public static <V, E extends GEdge<V>> List<V> postOrder(GDirectedGraph<V, E> g) {
		return postOrder(g, GraphNavigator.topDownNavigator());
	}
Returns the vertices of the given graph in post-order, which is the order the vertices
are last visited when performing a depth-first traversal.

@param g the graph
@return the vertices in post-order
Ghidra/Framework/Graph/src/main/java/ghidra/graph/algo/DepthFirstSorter.java