fix

openkriemy.py

@@ -78,7 +78,7 @@ async def on_message(event):
     try:
         command = parse_command(text)
     except ValueError:
-        if chess and (event.sender.id in chess.sessions or str(peer_id) in chess.sessions):
+        if chess and event.sender and (event.sender.id in chess.sessions or str(peer_id) in chess.sessions):
             reply = await event.get_reply_message()
             if reply and get_peer_id(reply.from_id) == await bot.get_peer_id("me") and reply.media:
                 text = text.strip()