public Set<Vertex> getNeighborhood(Set<Vertex> vs) {
		Set<Vertex> neighborhood = new HashSet<>(2 * vs.size());
		Iterator<Vertex> iter = vs.iterator();
		while (iter.hasNext()) {
			neighborhood.addAll(getNeighborhood(iter.next()));
		}
		return neighborhood;
	}
Returns a java.util.Set containing the vertices in the given Set and their
 neighbors.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/DirectedGraph.java