如何在pandas中获取层次索引序列中的值的索引

import pandas as pd

# 创建一个带有层次索引的DataFrame
data = {'A': [1, 2, 3, 4],
        'B': [5, 6, 7, 8]}
index = pd.MultiIndex.from_tuples([('Group1', 'Index1'), ('Group1', 'Index2'), ('Group2', 'Index3'), ('Group2', 'Index4')])
df = pd.DataFrame(data, index=index)

# 获取层次索引序列中的值的索引
level_values = df.index.get_level_values('Group1')
print(level_values)

Index(['Index1', 'Index2'], dtype='object')