Thanks, mr. Reedy for your response! I have already solved the issue.
Actually I had encountered this before and figured out the problem, but
unfortunately forgot when I encountered it again. I should have deleted
this issue from Python Bug community, but I thought it was not online since
I needed to complete some kind of form before it published on the site...
My bad!

On Sat, Dec 3, 2016 at 5:35 AM, Terry J. Reedy <report@bugs.python.org>
wrote:

>
> Terry J. Reedy added the comment:
>
> You code is buggy and will not run in Python because it does import
> messagebox.  Add
>
> from tkinter import messagebox
>
> If you only tested with IDLE before freezing, you might have missed the
> bug in your program because of a bug in IDLE, now fixed in 2.7 and 3.5+.
>
> ----------
> nosy: +terry.reedy
> resolution:  -> not a bug
> stage:  -> resolved
> status: open -> closed
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue28829>
> _______________________________________
>