docs: def check_images(data):
      """
      Check and reformat input images if needed
      """
      if isinstance(data, ndarray):
          data = fromarray(data)
      
      if not isinstance(data, Images):
          data = fromarray(asarray(data))
  
      if len(data.shape) not in set([3, 4]):
          raise Exception('Number of image dimensions %s must be 2 or 3' % (len(data.shape)))
  
      return data