如何收缩NetworkX中只有2条边的节点？

import networkx as nx

# 创建一个示例图
G = nx.Graph()
G.add_edges_from([(1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7)])

# 收缩只有2条边的节点
while True:
    degree_dict = dict(G.degree())
    nodes_to_contract = [node for node, degree in degree_dict.items() if degree == 2]
    if len(nodes_to_contract) == 0:
        break
    for node in nodes_to_contract:
        neighbors = list(G.neighbors(node))
        edge1 = (neighbors[0], node)
        edge2 = (node, neighbors[1])
        G = nx.contracted_nodes(G, *neighbors, self_loops=False)
        G.add_edge(*edge1)
        G.add_edge(*edge2)

# 打印收缩后的图信息
print(G.edges())