new_contents: import sys
  
  alphabet = "abcdefghijklmnopqrstuvwxyz"
  ciphered = ""
  
  for l in sys.argv[1]:
      if l in alphabet:
          ciphered += alphabet[26 - alphabet.index(l)]
      else:
          ciphered += l
  
  print ciphered
  
subject: Create caesar.py