new_contents: import unittest
  import urllib
  import requests
  import logging
  import re
  import urllib
  import os
  import os.path
  import Image
  import ImageDraw
  
  # Default is warning, it's to suppress requests INFO log
  logging.basicConfig(format='%(message)s')
  
  
  def solution():
      url = 'http://www.pythonchallenge.com/pc/return/cave.jpg'
      urllib.urlretrieve(url, 'cave.jpg')
      image_file = Image.open('cave.jpg')
      new_image = Image.new('RGB', (640, 480), 'black')
      new_image_stroke = ImageDraw.Draw(new_image)
      for y in range(480):
          for x in range(640):
              if y % 2 == 0 and x % 2 == 0 or y % 2 == 1 and x % 2 == 1:
                  new_image.putpixel((x, y), image_file.getpixel(x, y))
      new_image.save('cave_edited.jpg')
      return 'evil'
  
  class SolutionTest(unittest.TestCase):
  
      def setUp(self):
          self.prefix = "http://www.pythonchallenge.com/pc/return/"
          self.suffix = ".html"
  
      def test_solution(self):
          actual = solution()
          expected = 'evil'
          cred = ('huge', 'file')
          self.assertEquals(actual, expected)
          origin_url = ''.join([self.prefix, 'evil', self.suffix])
          try:
              r = requests.get(origin_url, auth=cred)
          except:
              raise
          self.assertTrue(r.ok)
          next_entry = [re.sub(r'(.*)URL=(.*)\.html\"\>', r'\2', line)
                        for line in r.iter_lines() if re.match(r'.*URL.*', line)]
          r.close()
          if len(next_entry) != 0:
              r = requests.get(
                  ''.join([self.prefix, next_entry[0], self.suffix], auth=expected))
              logging.warn('Level 12 is %s with %s' % (r.url, cred))
          else:
              logging.warn('Level 12 is %s with %s' % (origin_url, cred))
  
  
  if __name__ == "__main__":
      unittest.main(failfast=True)
  
subject: add level 11 (WIP)