今天实践了下Altair,却不知道怎么将图片输出，有懂的吗？代码如下：

-*- coding: utf-8 -*-

print("="*70)
print(" Hello, Python world! I am coming!")
print("="*70)

import pandas as pd
import altair as alt
data = pd.DataFrame({'contry_id': [1,2,3,4,5,6],
'population':[1,100,200,300,400,500],
'income': [1000,50,200,300,200,150]})
print(data)
categorical_chart= alt.Chart(data).mark_circle(size = 200).encode(
x = 'population:Q',
color = 'contry_id:Q')
print(categorical_chart)

你这样图片是显示不出来的