add try catch on langggraph client

app.py

@@ -12,11 +12,18 @@ async def on_start():
     langraph_client = get_client(
         url=LANGGRAPH_DEPLOYMENT
     )
-    assistants = await langraph_client.assistants.search(
-        graph_id="simple_rag", metadata={"created_by": "system"}
-    )
-
-    thread = await langraph_client.threads.create()
+    
+    try:
+        assistants = await langraph_client.assistants.search(
+            graph_id="simple_rag", metadata={"created_by": "system"}
+        )
+
+        thread = await langraph_client.threads.create()
+    except Exception as e:
+        print(f"Error occurred while creating assistant or thread: {str(e)}")
+        # You might want to handle the error appropriately here
+        # For example, you could raise a custom error or return a default value
+        raise
 
     cl.user_session.set("langraph_client", langraph_client)
     cl.user_session.set("assistant_id", assistants[0]["assistant_id"])