input: 
  from Crypto.Cipher import AES
  
  key = b'Sixteen byte key'
  
  def encrypt(plaintext: str) -> bytes:
      """Encrypt a given string using the AES encryption algorithm in ECB mode.
      >>> encrypt(b'Hello, World!')
      b'\\xe5\\xd5x\\xef6Py$\\xe0\\xc0r6Gq\\xd3\\x12'
      """
      cipher = AES.new(key, AES.MODE_ECB)
      return cipher.encrypt(plaintext)
  
  def decrypt(ciphertext: bytes) -> str:
      """Decrypt a given ciphertext using the AES decryption algorithm in ECB mode.
      >>> decrypt(b'\\xe5\\xd5x\\xef6Py$\\xe0\\xc0r6Gq\\xd3\\x12')
      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).decode('utf-8')
  