Define a function named posterize. This function expects an image and a tuple of RGB values as arguments.

def posterize(image, rgb_tuple):
  """
  This function takes an RGB image and converts it to a posterized image.
  """
  # Define your new image using a copy of the original image
  new_image = image.copy()
  # Define the RGB threshold values
  red_threshold = rgb_tuple[0]
  green_threshold = rgb_tuple[1]
  blue_threshold = rgb_tuple[2]
  # Use a nested for-loop to loop through the rows and columns of the image
  for row in range(new_image.shape[0]):
    for col in range(new_image.shape[1]):
      # Use if statements to determine whether to assign 0 or 255 to each
      # channel in the image
      if new_image[row][col][0] < red_threshold:
        new_image[row][col][0] = 0
      else:
        new_image[row][col][0] = 255
      if new_image[row][col][1] <