如何在Python中保持标识列不变的同时，从多个数据帧中添加多个列？

import pandas as pd

# 创建多个数据帧
df1 = pd.DataFrame({'ID': [1, 2, 3, 4],
                    'Name': ['Alice', 'Bob', 'Charlie', 'David']})

df2 = pd.DataFrame({'ID': [1, 2, 3, 4],
                    'Age': [25, 30, 35, 40]})

df3 = pd.DataFrame({'ID': [1, 2, 3, 4],
                    'City': ['New York', 'London', 'Paris', 'Tokyo']})

# 使用merge函数按照标识列合并数据帧
merged_df = pd.merge(df1, df2, on='ID')
merged_df = pd.merge(merged_df, df3, on='ID')

# 添加多个列
merged_df['Salary'] = [5000, 6000, 7000, 8000]
merged_df['Department'] = ['HR', 'IT', 'Marketing', 'Finance']

# 打印结果
print(merged_df)

   ID     Name  Age       City  Salary  Department
0   1    Alice   25   New York    5000          HR
1   2      Bob   30     London    6000          IT
2   3  Charlie   35      Paris    7000   Marketing
3   4    David   40      Tokyo    8000     Finance