input: 
  from Crypto.Cipher import AES
  
  key = b'Sixteen byte key'
  
  def encrypt(plaintext: str) -> bytes:
      """Encrypts the given plaintext using AES encryption algorithm.
      >>> encrypt(b'Hello world!')
      b'\xcf/\xaaAQ"[ \xf0qE\xaaYn\xa3'
      """
      cipher = AES.new(key, AES.MODE_ECB)
      return cipher.encrypt(plaintext)
  
  def decrypt(ciphertext: bytes) -> bytes:
      """Decrypts the given ciphertext using AES decryption algorithm.
      >>> decrypt(b'\xcf/\xaaAQ"[ \xf0qE\xaaYn\xa3')
      b'Hello world!'
      """
      cipher = AES.new(key, AES.MODE_ECB)
      return cipher.decrypt(ciphertext)
  
output:     
      cipher = AES.new(key, AES.MODE_ECB)
      return cipher.decrypt(ciphertext)
  