code: def Decrypt(self, data):
      
      decryptor = self.GetDecryptor()
  
      try:
        padded_data = decryptor.update(data) + decryptor.finalize()
        return self.UnPad(padded_data)
      except ValueError as e:
        raise CipherError(e)
docs: A convenience method which pads and decrypts at once.