how to change background in turtle python code example

Example 1: how to change background color in python turtle

import turtle
wn=turtle.Screen()
wn.bgcolor("black")
wn.title("This is my screen title!")

Example 2: python turtle background image

import turtle

window = turtle.Screen()
window.bgpic('source image') # image should be PNG or GIF
window.update() # to show the image


mainloop()