clip时，当地图边界范围大于数据范围时会导致裁切后大范围留白，求问怎么解决 about cnmaps HOT 4 CLOSED

import matplotlib.pyplot as plt
import cartopy.crs as ccrs

from cnmaps import get_adm_maps, clip_contours_by_map, draw_maps, MapPolygon
from cnmaps.sample import load_temp
from shapely.geometry import Polygon

fig = plt.figure(figsize=(6, 5), dpi=300)
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], projection=ccrs.PlateCarree())
lons, lats, data = load_temp()
cs = ax.contourf(lons, lats, data)

boundary = MapPolygon(
    [Polygon([[70, 55], [140, 55], [140, 40], [70, 40], [70, 55]])]
) & get_adm_maps(country="中华人民共和国", only_polygon=True, record="first")

draw_maps(get_adm_maps(country="中华人民共和国"), ax)
clip_contours_by_map(cs, boundary, ax)
ax.set_extent([70, 140, 40, 55], crs=ccrs.PlateCarree())
fig.savefig("./test.png", bbox_inches="tight")