code: def validate_image(image, number_tiles):
      
      TILE_LIMIT = 99 * 99
  
      try:
          number_tiles = int(number_tiles)
      except:
          raise ValueError('number_tiles could not be cast to integer.')
  
      if number_tiles > TILE_LIMIT or number_tiles < 2:
          raise ValueError('Number of tiles must be between 2 and {} (you \
                            asked for {}).'.format(TILE_LIMIT, number_tiles))
docs: Basic sanity checks prior to performing a split.