这是我的代码，其中包含我想使用pandas.DataFrame.groupby执行任务的数据
import pandas as pd
data = {'employees_no': [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13],
'employees_name': ['Jugal Sompura', 'Maya Rajput', 'Chaitya Panchal', 'Sweta Rampariya', 'Prakshal Patel', 'Dhruv Panchal', 'Prachi Desai', 'Krunal Gosai', 'Hemil Soni', 'Gopal Pithadia', 'Jatin Shah', 'Raj Patel', 'Shreya Desai'],
'department_name': ['HR', 'Administrative Assistant', 'Production', 'Accountant', 'Production', 'Engineer', 'Finance', 'Engineer', 'Quality Assurance', 'Engineer', 'Engineer', 'Customer Service', 'CEO'],
'salary': [130000.0, 65000.0, 45000.0, 65000.0, 47000.0, 40000.0, 90000.0, 45000.0, 35000.0, 45000.0, 30000.0, …