private List<V> getVerticesPostOrder() {
		Set<V> seeds = navigator.getSources(g);
		for (V v : seeds) {
			postOrderVisit(v);
		}

		for (V v : g.getVertices()) {
			if (!visited.contains(v)) {
				postOrderVisit(v);
			}
		}
		return new ArrayList<>(visited);
	}
Returns the vertices of the given graph in pre-order, which is the order the vertices
are encountered when performing a depth-first traversal.

@param g the graph
@param navigator the knower of the direction the graph should be traversed
@return the vertices in pre-order
Ghidra/Framework/Graph/src/main/java/ghidra/graph/algo/DepthFirstSorter.java