Multiple Vincent/Vega charts in a popup?

I'm trying to add two Vincent bar charts in a popup using Vega, one on top of the other. The two methods below are not working:

# Adding both charts to add_child: This only renders the first chart
m.add_child( folium.CircleMarker(
        location = [df['latitude'], df['longitude']],
        popup = folium.Popup(max_width = 450).add_child(chart1, chart2)
  ))

# Method-chaining: This only renders the second chart
m.add_child( folium.CircleMarker(
        location = [df['latitude'], df['longitude']],
        popup = folium.Popup(max_width = 450).add_child(chart1, name = 'c1').add_child(chart2, name = 'c2')
    ) )

Is there a way to accomplish this?

首先从 issue 中的两个示例入手，跟踪 Popup.add_child，并检查 popup 子项是如何渲染的。当单个 popup 能够可靠地同时显示两个 Vincent/Vega 图表，而不只是第一个或第二个图表时，这项工作就完成了。