如何在MultiIndex中对列熊猫进行数学运算？

import pandas as pd

df = pd.DataFrame({'index1': ['A', 'A', 'B', 'B'],
                   'index2': ['X', 'Y', 'X', 'Y'],
                   'column': [1, 2, 3, 4]})
df.set_index(['index1', 'index2'], inplace=True)

# 求和
sum_result = df['column'].sum()

# 平均值
mean_result = df['column'].mean()

# 最大值
max_result = df['column'].max()

# 最小值
min_result = df['column'].min()

# 对两列进行相加操作
add_result = df[['column1', 'column2']].apply(lambda x: x['column1'] + x['column2'], axis=1)