Flip a coin to change pixels

hope everyone is doing fine.

i am building a program in jython. I have a picture that has random pixel change.

def setPixelToBlack(picture):
  pixels = getPixels(picture)
  for index in range(0,len(pixels)):
  pixel = pixels[index]
  color = makeColor(0,0,0)
  setColor(pixel,color)

This will set the entire picture black. However, what I want to do is, there is a toss. If its heads, the pixel will change to black. If it is tails, the pixel color will remain same. This is to be done using import statement.