int index(Vertex v) {
		try {
			return keyIndices.get(v.key());
		}
		catch (NoValueException exc) {
			return -1;
		}
	}
Return the internal index of the given vertex within this edge set.
@return the internal index of o.
@throws ClassCastException if the object is not a Vertex.
@throws NoValueException if the KeyedObject is not in the VertexSet.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/VertexSet.java