Finding problems when making a simple payroll program

from __future__ import annotations
from typing import List

fixed_rate_month = 1800  # Full-Time
fixed_rate_hour = 7  # Shift Worker

hours_worked = []

emp_count = 0   # TODO ARRANGE


class Employee:
    EMPLOYEES: List[Employee] = []

    def __init__(self, name: str, surname: str, emp_type: str):
        self.name: str = name
        self.surname: str = surname
        self.emp_type = emp_type
        self.__id: int = Employee.__get_next_id()
        self.__pay_details: dict = {}
        Employee.EMPLOYEES.append(self)

    @property  # This property allows read-only access to __id (getter)
    def id(self) -> int:  # This returns an int (type hint)
        return self.__id

    @property
    def pay_details(self) -> dict:
        return self.__pay_details

    @staticmethod  # This keeps just one copy of the method in the class
    def __get_next_id() -> int:
        next_id = 0
        for e in Employee.EMPLOYEES:
            next_id = e.__id if e.__id > next_id else next_id
        next_id += 1
        return next_id

    @staticmethod
    def get_by_id(employee_id: int) -> Employee:
        for e in Employee.EMPLOYEES:
            if e.__id == employee_id:
                return e


def show_menu():
    while True:
        print('\nPayroll System')
        print('---------------')
        print('1. Add an Employee')
        print('2. Show Employees')
        print('3. Exit')
        response = input('Choice >')

        if response == '1':
            add_employee()
        elif response == '2':
            show_employees()
        elif response == '3':
            pass
        else:
            print('Invalid Option!')


def add_employee():
    global emp_count

    checker = False
    print('\nAdding an Employee')
    name = input('Name >')
    surname = input('Surname >')

    emp_type = ''  # So the variable is created
    while checker is False:
        print('\nWhich type of employee is', name, surname, '?')
        print('     Full-Time Employee (FT)')
        print('     Shift Worker (SW)')
        emp_type = input(str('\nEmployment Type >'))

        if emp_type != 'FT' and emp_type != 'SW' and emp_type != 'ft' and emp_type != 'sw':
            print('Invalid Option! Please try again.')
        else:
            checker = True
            if emp_type == 'SW' or emp_type == 'sw':
                print('\nHow many hours has', name, surname, 'worked?')
                hours_worked.append(int(input('Hours >')))
                print(emp_count)

    if checker:
        # Only do this if the checker works
        Employee(name, surname, emp_type)
        emp_count += 1


def show_employees(employee_id: int) -> None:       # TODO ARRANGE LATER'
    e = Employee.get_by_id(employee_id)
    print('\n{0:3}\t{1:10}\t{2:10}\t{3:5}'.format('ID', 'Name', 'Surname', 'Emp. Type'))
    for e in Employee.EMPLOYEES:
        print('{0:03d}\t{1:10}\t{2:10}\t{3:<5.1}'.format(e.id, e.name, e.surname, e.emp_type))

    print('\nPay Details of Employee {0:03d} ({1} {2})'.format(e.id, e.name, e.surname))
    print('{0:10}\t{1:5}'.format('Gross Wage', 'Net Wage', 'Payslip Date'))
    for gross_wage, net_wage, ps_date in e.pay_details.items():
        print('{1:10}\t{1:<5}'.format(gross_wage, net_wage, ps_date))


show_menu()