如何为添加Cartopy shapely功能的GeoAxes添加图例？

import cartopy.crs as ccrs
import cartopy.feature as cfeature
import matplotlib.pyplot as plt
from shapely.geometry import Point

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())

ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE)
ax.add_feature(cfeature.BORDERS)

point = Point(lon, lat)
attributes = {'name': 'City', 'population': 1000000}

ax.plot(point.x, point.y, 'ro', transform=ccrs.PlateCarree())

legend_labels = ['City']
legend_styles = ['ro']
ax.legend(legend_styles, legend_labels)

plt.show()