new_contents: """Masking.
  
  Usage:
    masking.py IMAGE MASK
    masking.py (-h | --help)
    masking.py --version
  
  Options:
    -h --help     Show this screen.
    --version     Show version.
  """
  from docopt import docopt
  import scipy
  import numpy as np
  import math
  
  import skimage.io as io
  from skimage import transform
  
  def mask_image(image, mask):
      idx = (mask!=0)
      masked_image = np.zeros(image.shape)
      masked_image[idx] = image[idx]
      return masked_image
  
  if __name__ == '__main__':
      arguments = docopt(__doc__, version='Masking')
      image_path = arguments["IMAGE"]
      mask_path = arguments["MASK"]
  
      image = io.imread(image_path)
  
      mask = io.imread(mask_path, as_grey=True)
      mask = transform.rescale(mask, 4) #mammogram is x4 mask
  
      masked_image = mask_image(image, mask)
  
      io.imshow(masked_image)
      io.show()
  
subject: Add masking file test.