input: Write a python function to decrypt a given encoded message using a predefined shift list.
  assert decrypt('§ ¢ ') == 'decoded'
  assert decrypt('') == 'aaaaaa'
  assert decrypt('') == 'abcde'
output: def decrypt(encoded_message):
      shift_list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]
      decrypted_message = ''
      
      for i, char in enumerate(encoded_message):
          shift = shift_list[i % len(shift_list)]
          decrypted_char = chr(ord(char) - shift)
          decrypted_message += decrypted_char
      
      return decrypted_message