Some imports were missing

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

squinnondation/messages.py

@@ -1,9 +1,11 @@
 # Copyright (C) 2020 by eichhornchen, ÿnérant
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-from typing import Any, List, Optional, Tuple
+from typing import Any, List, Optional
 from ipaddress import IPv6Address
 from enum import Enum
+import sys
+
 
 class TLV:
     """