new_contents: import base64
  import crypto
  import unittest
  
  
  class HammingDistance(unittest.TestCase):
  
      def runTest(self):
          b1 = b"this is a test"
          b2 = b"wokka wokka!!!"
          self.assertEqual(37.0, crypto.hamming_distance(b1, b2))
          self.assertEqual(
              (37 * 4.0) / 6, crypto.hamming_distance(b1, b2, b1, b2))
          self.assertEqual(
              (37 * 4.0) / 6, crypto.hamming_distance(b1, b1, b2, b2))
          self.assertEqual(0.0, crypto.hamming_distance(b1, b1, b1))
  
  
  class DetermineKeysize(unittest.TestCase):
  
      def runTest(self):
          with open("../data/6.txt") as f:
              b64 = f.read()
          b = base64.b64decode(b64)
          keysize, _ = crypto.determine_keysize(b)
          self.assertEqual(29, keysize)
  
  
  unittest.main()
  
subject: add some function unit tests