Define a Python function named mutate (), that takes a picture img as its argument. For each pixel in the image, get its red, green, and blue values, then replace the pixel by swapping its red and blue values and dividing the amount of green by 2. For example, a pixel with the red-green-blue values (100,70,200) would be replaced with one that has the red-green-blue values (200,35,100). Test out your new function on an image file of your choosing. What does it do to the image?