public AttributedVertex addVertex(String id, String vertexName) {
		if (vertexMap.containsKey(id)) {
			AttributedVertex vertex = vertexMap.get(id);
			vertex.setName(vertexName);
			return vertex;
		}
		AttributedVertex newVertex = new AttributedVertex(id, vertexName);
		addVertex(newVertex);
		return newVertex;
	}
Adds a new vertex with the given id and name.  If a vertex already exists with that id,
then that vertex will be returned, but with its name changed to the given name.

@param id the unique vertex id that the graph should have a vertex for.
@param vertexName the name to associate with this vertex
@return either an existing vertex with that id, or a newly added vertex with that id
Ghidra/Framework/Graph/src/main/java/ghidra/service/graph/AttributedGraph.java