class HRManagementSystem:
    """
    This is a class as personnel management system that implements functions such as adding, deleting, querying, and updating employees
    """
    def __init__(self):
        self.employees = {}

    def add_employee(self, employee_id, name, position, department, salary):
        """
        Add a new employee to the HRManagementSystem.
        :param employee_id: The employee's id, int.
        :param name: The employee's name, str.
        :param position: The employee's position, str.
        :param department: The employee's department, str.
        :param salary: The employee's salary, int.
        :return: If the employee is already in the HRManagementSystem, returns False, otherwise, returns True.
        >>> hrManagementSystem = HRManagementSystem()
        >>> hrManagementSystem.add_employee(1, 'John', 'Manager', 'Sales', 100000)
        True
        >>> hrManagementSystem.add_employee(1, 'John', 'Manager', 'Sales', 100000)
        False

        """

        if employee_id in self.employees:
            return False
        else:
            self.employees[employee_id] = {
                'name': name,
                'position': position,
                'department': department,
                'salary': salary
            }
            return True

    def remove_employee(self, employee_id):
        """
        Remove an employee from the HRManagementSystem.
        :param employee_id: The employee's id, int.
        :return: If the employee is already in the HRManagementSystem, returns True, otherwise, returns False.
        >>> hrManagementSystem = HRManagementSystem()
        >>> hrManagementSystem.employees = {1: {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 100000}}
        >>> hrManagementSystem.remove_employee(1)
        True
        >>> hrManagementSystem.remove_employee(2)
        False

        """

        if employee_id in self.employees:
            del self.employees[employee_id]
            return True
        else:
            return False

    def update_employee(self, employee_id: int, employee_info: dict):
        """
        Update an employee's information in the HRManagementSystem.
        :param employee_id: The employee's id, int.
        :param employee_info: The employee's information, dict.
        :return: If the employee is already in the HRManagementSystem, returns True, otherwise, returns False.
        >>> hrManagementSystem = HRManagementSystem()
        >>> hrManagementSystem.employees = {1: {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 100000}}
        >>> hrManagementSystem.update_employee(1, {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 20000})
        True
        >>> hrManagementSystem.update_employee(2, {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 20000})
        False

        """
 int, employee_info: dict):
        employee = self.get_employee(employee_id)
        if employee == False:
            return False
        else:
            for key, value in employee_info.items():
                if key not in employee:
                    return False
            for key, value in employee_info.items():
                employee[key] = value
            return True

    def get_employee(self, employee_id):
        """
        Get an employee's information from the HRManagementSystem.
        :param employee_id: The employee's id, int.
        :return: If the employee is already in the HRManagementSystem, returns the employee's information, otherwise, returns False.
        >>> hrManagementSystem = HRManagementSystem()
        >>> hrManagementSystem.employees = {1: {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 100000}}
        >>> hrManagementSystem.get_employee(1)
        {'name': 'John', 'position': 'Manager', 'department': 'Sales', 'salary': 100000}
        >>> hrManagementSystem.get_employee(2)
        False

        """

        if employee_id in self.employees:
            return self.employees[employee_id]
        else:
            return False

    def list_employees(self):
        employee_data = {}
        if self.employees:
            for employee_id, employee_info in self.employees.items():
                employee_details = {}
                employee_details["employee_ID"] = employee_id
                for key, value in employee_info.items():
                    employee_details[key] = value
                employee_data[employee_id] = employee_details
        return employee_data

Method:
def list_employees(self):
        employee_data = {}
        if self.employees:
            for employee_id, employee_info in self.employees.items():
                employee_details = {}
                employee_details["employee_ID"] = employee_id
                for key, value in employee_info.items():
                    employee_details[key] = value
                employee_data[employee_id] = employee_details
        return employee_data

Summary: List all employees' information in the HRManagementSystem.