old_contents: from Crypto.Cipher import AES
  from base64 import b64decode, b64encode
  
  
  class aes128cbc(object):
  
      _key = None
      _iv = None
  
      def __init__(self, key, iv):
          """
          Advanced Encryption Standard object
          """
          self._bs = 16  # Block size
  
          if key is None:
              raise ValueError('Missing AES key')
          else:
              self._key = key
  
          if iv is None:
              raise ValueError('Missing AES initialization vector')
          else:
              self._iv = iv
  
      def encrypt(self, msg):
          msg = self._pad(self.str_to_bytes(msg))
          crypt = AES.new(self._key, AES.MODE_CBC, self._iv)
          return b64encode(self._iv + crypt.encrypt(msg)).decode('utf-8')
  
      def decrypt(self, msg):
          msg = b64decode(msg)
          crypt = AES.new(self._key, AES.MODE_CBC, self._iv)
          return self._unpad(crypt.decrypt(msg[self._bs:])).decode('utf-8')
  
      def _pad(self, s):
          return s + (self._bs - len(s) % self._bs) * self.str_to_bytes(chr(
              self._bs - len(s) % self._bs))
  
      def _unpad(self, s):
          return s[:-ord(s[len(s)-1:])]
  
      def str_to_bytes(self, s):
          u_type = type(b''.decode('utf8'))
          if isinstance(s, u_type):
              return s.encode('utf8')
          return s
  
new_contents: from Crypto.Cipher import AES
  from base64 import b64decode, b64encode
  
  
  class aes128cbc(object):
  
      _key = None
      _iv = None
  
      def __init__(self, key, iv):
          """
          Advanced Encryption Standard object
          """
          self._bs = 16  # Block size
  
          if key is None:
              raise ValueError('Missing AES key')
          else:
              self._key = key
  
          if iv is None:
              raise ValueError('Missing AES initialization vector')
          else:
              self._iv = iv
  
      def encrypt(self, msg):
          msg = self._pad(self.str_to_bytes(msg))
          crypt = AES.new(self._key, AES.MODE_CBC, self._iv)
          return b64encode(crypt.encrypt(msg)).decode('utf-8')
  
      def decrypt(self, msg):
          msg = b64decode(msg)
          crypt = AES.new(self._key, AES.MODE_CBC, self._iv)
          return self._unpad(crypt.decrypt(msg)).decode('utf-8')
  
      def _pad(self, s):
          return s + (self._bs - len(s) % self._bs) * self.str_to_bytes(chr(
              self._bs - len(s) % self._bs))
  
      def _unpad(self, s):
          return s[:-ord(s[len(s)-1:])]
  
      def str_to_bytes(self, s):
          u_type = type(b''.decode('utf8'))
          if isinstance(s, u_type):
              return s.encode('utf8')
          return s
  
subject: fix TypeError