public boolean add(Edge e, double weight) {
		double wt = getWeight(e);
		super.add(e);
		setWeight(e, wt + weight);
		return true;
	}
Add an edge. If successful (i.e. that edge does not appear in the graph),
then set the weight to the specified value.

@return true if edge added succesfuly.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/WeightedDigraph.java