@Override
	public boolean add(Edge e) {
		if (!allowLoops && (e.from() == e.to())) {
			return false;
		}
		Edge[] ft = this.getEdges(e.from(), e.to());
		if (ft.length == 0) {
			return super.add(e);
		}
		return this.setWeight(ft[0], this.getWeight(ft[0]) + this.getDefaultEdgeWeight());
	}
Add an edge with the default edge weight. 

If an edge from and to the vertices
specified by the edge already exists in the graph, 
then the edge weight in increased by the default value.
@param e the edge to add.
@return true if the edge was added sucessfully.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/SimpleWeightedDigraph.java