code: def _encrypt_from_parts(self, data, iv):
          
          padder = padding.PKCS7(algorithms.AES.block_size).padder()
          padded_data = padder.update(data) + padder.finalize()
          encryptor = Cipher(
              algorithms.AES(self._encryption_key), modes.CBC(iv),
              self._backend).encryptor()
          ciphertext = encryptor.update(padded_data) + encryptor.finalize()
  
          return self._signer.sign(iv + ciphertext)
docs: :type data: bytes
          :type iv: bytes
          :rtype: any