input: def shift_encode(s: str):
      """
      return a string where each character is shifted by 5 positions in the alphabet.
      """
      return "".join([chr(((ord(ch) + 5 - ord('a')) % 26) + ord('a')) for ch in s])
  
  
  def shift_decode(s: str):
      """
      takes a string that was encoded with shift_encode function and returns the original string.
      """
output:     return "".join([chr(((ord(ch) - 5 - ord('a')) % 26) + ord('a')) for ch in s])