    def aes_cbc_encrypt(plain_text: bytes, key: bytes, iv: bytes = b''):
        if len(iv) == 0:
            iv = AESHandler.generate_iv()
        cipher = AES.new(key=key, mode=AES.MODE_CBC, iv=iv)
        return cipher.IV, cipher.encrypt(pad(plain_text, AES.block_size))