tk.py

from tkinter import *

def click():
    def add_holiday():
        ibox.insert(END, entry2.get())
        win1.destroy()
    win1 = Toplevel()
    win1.title('Введення нового свята')
    label3 = Label(win1, text = 'Введiть нове свято')
    label3.pack(padx = 3, pady = 3)
    entry2 = Entry(win1)
    entry2.pack(padx = 3, pady = 3)
    button3 = Button(win1, text = 'Додати', command = add_holiday)
    button3.pack(padx = 3, pady = 3)
    
def congrats():
    def thank_you():
        win2.destroy()
    win2 = Toplevel()
    win2.title('Вiтання!')
    
    select = ibox.curselection()    
    lbl = Label(win2, text = entry1.get() + ', ' + ibox.get(select))
    lbl.pack(padx = 3, pady = 3)
    
    btn = Button(win2, text = 'Дякую!', command = thank_you)
    btn.pack(padx = 3, pady = 3)

root = Tk()

label1 = Label(root, text = 'Виберiть вiтання')
label1.grid(row = 0, column = 2, sticky = 'e')

label2 = Label(root, text = "Введiть iм'я")
label2.grid(row = 1, column = 0, sticky = 'e')
entry1 = Entry(root)
entry1.grid(row = 1, column = 1)

ibox = Listbox(root, height = 4)
ibox.insert(0, 'з днем народження!')
ibox.insert(1, 'з Новим роком!')
ibox.grid(row = 1, column = 2, padx = 3, pady = 3)

button1 = Button(root, text = 'Привiтання!', command = congrats)
button1.grid(row = 2, column = 1)

button2 = Button(root, text = 'Додати вiтання', command = click)
button2.grid(row = 2, column = 2)