如何使用Petgraph节点所连接的节点来迭代它们的边？

use petgraph::Graph;
use petgraph::graph::NodeIndex;

fn main() {
    // 创建一个无向图
    let mut graph = Graph::new_undirected();

    // 添加节点
    let node_a = graph.add_node("A");
    let node_b = graph.add_node("B");
    let node_c = graph.add_node("C");

    // 添加边
    graph.add_edge(node_a, node_b, 1);
    graph.add_edge(node_a, node_c, 2);

    // 获取节点的邻居节点
    let neighbors = graph.neighbors(node_a);

    // 迭代邻居节点的边
    for neighbor in neighbors {
        let edges = graph.edges(neighbor);
        for edge in edges {
            println!("Edge: {:?}", edge);
        }
    }
}