如何在python中的单独列的数据帧中插入pos标签？

import pandas as pd

df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})

df['pos'] = ['pos1', 'pos2', 'pos3']

import pandas as pd

df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})
df['pos'] = ['pos1', 'pos2', 'pos3']

print(df)

   A  B   pos
0  1  4  pos1
1  2  5  pos2
2  3  6  pos3