text: from matasano import xor_strings
  
  def encrypt_repeated_xor(text, key):
      output = ''
      for i, c in enumerate(text):
          indice = i % len(key)
          output += '{:02x}'.format(ord(c) ^ ord(key[indice]))
      return output
  
  text = '''Burning 'em, if you ain't quick and nimble
  I go crazy when I hear a cymbal'''
  
  result = encrypt_repeated_xor(text, 'ICE')
  assert result == '0b3637272a2b2e63622c2e69692a23693a2a3c6324202d623d63343c2a26226324272765272a282b2f20430a652e2c652a3124333a653e2b2027630c692b20283165286326302e27282f'
  