Close only if not already

src/EdgeGPT.py

@@ -185,8 +185,9 @@ class ChatHub:
         """
         Close the connection
         """
-        await self.wss.close()
-
+        if self.wss:
+            if not self.wss.closed:
+                 await self.wss.close()
 
 class Chatbot:
     """