input: def cyclic_shift_encode(s: str):
      """
      Encodes a string by rotating groups of three characters.
      """
      # Break the string into chunks. Each chunk contains 3 characters.
      chunks = [s[(3 * i):min((3 * i + 3), len(s))] for i in range((len(s) + 2) // 3)]
      # Rotate each chunk's characters. Do not shift if the chunk has fewer than 3 characters.
      chunks = [(chunk[1:] + chunk[0]) if len(chunk) == 3 else chunk for chunk in chunks]
      return "".join(chunks)
  
  
  def cyclic_shift_decode(s: str):
      """
      Decodes a string that was encoded with the cyclic_shift_encode function.
      """
output:     chunks = [s[(3 * i):min((3 * i + 3), len(s))] for i in range((len(s) + 2) // 3)]
      chunks = [(chunk[-1] + chunk[:-1]) if len(chunk) == 3 else chunk for chunk in chunks]
      return "".join(chunks)