在python中查找平面图的面

import networkx as nx

# 创建一个空的图
G = nx.Graph()

# 添加图的边
G.add_edges_from([(1, 2), (2, 3), (3, 1)])

# 创建一个空的面列表
faces = []

# 遍历图的每一条边
for edge in G.edges():
    # 检查边是否已经被访问过
    if not G.edges[edge].get('visited', False):
        # 标记边为已访问
        G.edges[edge]['visited'] = True
        
        # 创建一个临时的面列表
        face = [edge]
        
        # 从当前边的一个顶点开始遍历相邻的边
        current_edge = edge
        while True:
            # 获取当前边的另一个顶点
            current_node = current_edge[1]
            
            # 查找相邻的边
            next_edge = None
            for neighbor_edge in G.edges(current_node):
                if not G.edges[neighbor_edge].get('visited', False):
                    next_edge = neighbor_edge
                    break
            
            # 如果找到相邻的边，则将其标记为已访问，并添加到临时的面列表中
            if next_edge:
                G.edges[next_edge]['visited'] = True
                face.append(next_edge)
                current_edge = next_edge
            else:
                # 如果没有找到相邻的边，则回到起始边，形成一个面
                face.append(edge)
                break
        
        # 将临时的面列表添加到面列表中
        faces.append(face)

# 打印结果
for face in faces:
    print(face)