new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  #xor file
  import sys
  
  class xor():
  
    def xor(self, orginal_file, xor_var, new_file):
      l = len(xor_var)
      data = bytearray(open(orginal_file, 'rb').read())
      result = bytearray((
        (data[i] ^ xor_var[i % l]) for i in range(0,len(data))
      ))
      localFile = open(new_file, 'w')
      localFile.write(result)
      localFile.close()
  
  
  if __name__ == '__main__':
    try:
      orginal_file = sys.argv[1]
      new_file = sys.argv[2]
      ##xor_var bytes are currently hardcoded
      xor_var = bytearray([0xde,0xad,0x13,0x37])
      transform = xor()
      transform.xor(orginal_file, xor_var, new_file)
    except IndexError:
      print('Usage: xor.py <input_file> <output_file>')
      print('Note: xor byte values are currently hardcoded!')
      sys.exit(1)
  
subject: Create xor.py