input: 
  def encrypt_and_decrypt(text: str) -> (bytes, str):
      """Encrypt a given string using AES encryption and then decrypt it back to the original string.
      Use a predefined key for AES encryption and decryption.
      >>> encrypt_and_decrypt('Hello, World!')
      (b'\\x9f\\x1e\\xb4\\x9eX":&\\xf2Q\\xd9\\xd8la\\x83]', 'Hello, World!')
      """
  
output:     from Crypto.Cipher import AES
      from Crypto.Util.Padding import pad, unpad
      import os
  
      key = os.urandom(16)
      cipher = AES.new(key, AES.MODE_CBC)
      ciphertext = cipher.encrypt(pad(text.encode(), AES.block_size))
      decrypted_text = unpad(cipher.decrypt(ciphertext), AES.block_size).decode()
      return ciphertext, decrypted_text