使用OSMnx按bbox截断图：如何在边界创建虚拟节点？

我尝试使用OSMnx按bbox（边界框）截断路网图，按官方文档操作可正常运行，复现代码如下：

import numpy as np
import osmnx as ox
import geopandas as gpd
import networkx as nx
import matplotlib.pyplot as plt

N, S, E, W = 1.3235381983186159, 1.319982801681384, \
                           103.85361309942331 , 103.84833190057668,
graph = ox.graph_from_bbox(N, S, E, W, \
                           network_type='drive')
nodes= ox.graph_to_gdfs(graph, nodes=True, edges=False)
edges= ox.graph_to_gdfs(graph, edges=True, nodes=False)
fig, ax = ox.plot.plot_graph(
                graph,
                ax=None,
                figsize=(10, 10),
                bgcolor="white",
                node_color="red",
                node_size=5,
                node_alpha=None,
                node_edgecolor="none",
                node_zorder=1,
                edge_color="black",
                edge_linewidth=0.1,
                edge_alpha=None,
                show=False,
                close=False,
                save=False,
                bbox=None,
            )
W_ = W + (E-W) * 0.8
S_ = S + (N-S)*0.7
width = (E - W)*0.07 
height = (N - S)*0.1 

rect = plt.Rectangle((W_, S_), width, height, facecolor="green", alpha=0.3, edgecolor=None)
ax.add_patch(rect)
plt.show()

g_truncated = ox.truncate.truncate_graph_bbox(graph, S_ + height, S_, W_+width, W_, truncate_by_edge=False)
ox.plot_graph(g_truncated)

当前截断后的图如图所示，我希望提取子图时在边界处创建虚拟节点，得到如图所示的包含6个黑色节点的目标子图。考虑到OSMnx的广泛应用，是否存在简便直接的实现方法？

内容的提问来源于stack exchange，提问作者lifezbeautiful