如何用folium在html上添加图例？

import folium

# 创建地图对象
m = folium.Map(location=[38.907,-77.037], zoom_start=12)

# 创建图例对象
legend_html = '''
     <div style="position: fixed; 
                 bottom: 50px; left: 50px; width: 100px; height: 90px; 
                 border:2px solid grey; z-index:9999; font-size:14px;
                 ">&nbsp; Legend <br>
       &nbsp; Marker 1 &nbsp; <i class="fa fa-map-marker fa-2x"
                     style="color:green"></i><br>
       &nbsp; Marker 2 &nbsp; <i class="fa fa-map-marker fa-2x"
                     style="color:red"></i>
      </div>
     '''

# 添加图例到地图
folium.Marker(
    location=[38.907,-77.037],
    popup='Marker 1',
    icon=folium.Icon(icon='green')
).add_to(m)

folium.Marker(
    location=[38.917,-77.047],
    popup='Marker 2',
    icon=folium.Icon(icon='red')
).add_to(m)

# 保存地图为html文件
m.get_root().html.add_child(folium.Element(legend_html))
m.save('map.html')