[Python] How to show a dialog when using a spinbox in tkinter

I have a spinbox in my tkinter application and I want to show a warning in certain circumstances

import tkinter as tk
from tkinter import ttk, messagebox

widgets = None
root = None

def main() -> None:
global widgets
global root

root = tk.Tk()
root.title('Spinbox')
root.geometry('400x400')
widgets = tk.IntVar()

spin_box = ttk.Spinbox(
root,
from_=1,
to=40,
textvariable=widgets,
command=_widgets_change,
)
spin_box.grid(row=0, column=0)

root.mainloop()


def _widgets_change() -> None:
if widgets.get() > 2:
root.update_idletasks()
result = messagebox.showwarning(
'',
'Too big',
parent=root
)
print(result)



if __name__ == '__main__':
main()


This works if I increase the value in the entry, but if I use the up-down button I get into a loop with the error

_tkinter.TclError: can't invoke "grab" command: application has been destroyed
​

How can I get around this?

(Linux - Manjaro)

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