Error when only 3 nodes in DiGraph about cspy HOT 1 CLOSED

G = nx.DiGraph(directed=True, n_res=2)
G.add_edge("Source", "A", res_cost=array([1, 2]), weight=0)
G.add_edge("A", "B", res_cost=array([1, 0.3]), weight=0)
G.add_edge("A", "C", res_cost=array([1, 0.1]), weight=0)
G.add_edge("B", "C", res_cost=array([1, 3]), weight=-10)
G.add_edge("A", "Sink", res_cost=array([1, 10]), weight=0)
max_res, min_res = [4, 20], [1, 0]
bidirec = BiDirectional(G, max_res, min_res, direction="both")
bidirec.run()
print(bidirec.path)