Python Tkinter Program to Create Minimum and Maximum Size Window

import tkinter as tk

root = tk.Tk()
root.title('Tkinter Window Demo')
root.geometry('640x480+200+200')

root.minsize(400, 400)    # minsize(minWidth, minHeight)
root.maxsize(640, 480)    # minsize(maxWidth, maxHeight)

root.mainloop()