Change Window Background Event in Python 3

from tkinter import *

from tkinter import messagebox

root = Tk()


#add an event to the button
def changeBGcolor():
    root.config(background="green")
#add a button
Button1 = Button(root, text="CHANGE BACKGROUND", height=2, width=20,
                 command = changeBGcolor)
Button1.place(x=50,y=50)

root.geometry("300x200")
root.mainloop