Implement a date setter in Tkinter

The source code is as follows.

import tkinter as tk
from tkinter import ttk
import datetime
import calendar

year_list = ['2020', '2021']
month_list = [str(date).zfill(2) for date in range(1, 13)]
date_list = [str(date).zfill(2) for date in range(1, 32)]
hours_list = [str(date).zfill(2) for date in range(24)]
minutes_list = [str(date).zfill(2) for date in range(60)]
seconds_list = [str(date).zfill(2) for date in range(60)]


def change_date():
    def inner(self):
        last_day = calendar.monthrange(int(cb_year.get()), int(cb_month.get()))[1]
        if int(cb_date.get()) > last_day:
            cb_date.set(str(last_day).zfill(2))
        cb_date.config(values=[str(date).zfill(2) for date in range(1, last_day+1)])

        #Output in datetime format
        # date = cb_year.get()+'-'+cb_month.get()+'-'+cb_date.get()+' '+cb_hours.get()+':'+cb_minutes.get()+':'+cb_seconds.get()
        # print("Date = ", date)
    return inner


root = tk.Tk()
root.title('Date Picker')


cb_year = ttk.Combobox(root, values=year_list, width=5, state='readonly')
cb_year.set(year_list[0])
cb_year.bind('<<ComboboxSelected>>', change_date())
cb_year.pack(side='left')

label_slash = ttk.Label(root, text='/')
label_slash.pack(side='left')

cb_month = ttk.Combobox(root, values=month_list, width=5, state='readonly')
cb_month.set(month_list[0])
cb_month.bind('<<ComboboxSelected>>', change_date())
cb_month.pack(side='left')

label_slash = ttk.Label(root, text='/')
label_slash.pack(side='left')

cb_date = ttk.Combobox(root, values=date_list, width=5, state='readonly')
cb_date.set(date_list[0])
cb_date.pack(side='left')

label_space = ttk.Label(root, text=' ')
label_space.pack(side='left')

cb_hours = ttk.Combobox(root, values=hours_list, width=5, state='readonly')
cb_hours.set(hours_list[0])
cb_hours.pack(side='left')

label_colon = ttk.Label(root, text=':')
label_colon.pack(side='left')

cb_minutes = ttk.Combobox(root, values=minutes_list, width=5, state='readonly')
cb_minutes.set(minutes_list[0])
cb_minutes.pack(side='left')

label_colon = ttk.Label(root, text=':')
label_colon.pack(side='left')

cb_seconds = ttk.Combobox(root, values=seconds_list, width=5, state='readonly')
cb_seconds.set(seconds_list[0])
cb_seconds.pack(side='left')

root.mainloop()

Differences in the last day depending on the year and month are handled by the calender module. After startup, the following screen will appear so you can select the date and time.

Thank you for reading until the end. Let's meet again.