如何使用递增的序列id创建新的pandas列，但在每个组中保持相同的值

import pandas as pd

df = pd.DataFrame({'group': ['A', 'A', 'A', 'B', 'B', 'C', 'C'],
                   'value': [1, 2, 3, 4, 5, 6, 7]})

df['new_column'] = df.groupby('group').cumcount()

import pandas as pd

df = pd.DataFrame({'group': ['A', 'A', 'A', 'B', 'B', 'C', 'C'],
                   'value': [1, 2, 3, 4, 5, 6, 7]})

df['new_column'] = df.groupby('group').cumcount()

print(df)

  group  value  new_column
0     A      1           0
1     A      2           1
2     A      3           2
3     B      4           0
4     B      5           1
5     C      6           0
6     C      7           1