import tkinter
import tkinter.simpledialog as dialog

root = tkinter.Tk()

button = tkinter.Button(root, text='Hello!')
button.pack()

root.update()

dialog = dialog.SimpleDialog(
    root,
    title='Test Dialog',
    text='Text...',
    default=0,
    buttons=[
        'Button0', 'Button1', 'Button2', 'Button3', 'Button4',
    ],
)

button.mainloop()

print('dialog:', dialog.num)