input: Write a python function to get closeness of a given color to a target color in RGB format.
  assert get_closeness_to_target((255, 0, 0), (255, 255, 0)) < 1
  assert get_closeness_to_target((0, 0, 255), (0, 255, 0)) > 1
  assert get_closeness_to_target((128, 128, 128), (128, 128, 128)) == 0
output: def get_closeness_to_target(color, target):
      return ((color[0] - target[0]) ** 2 + (color[1] - target[1]) ** 2 + (color[2] - target[2]) ** 2) ** 0.5