Update app.py

app.py

@@ -44,8 +44,10 @@ def generate_response(user_message, history=None):
             ] 
             yield chat, history
         else:
-            raise HTTPError(f"Request id: {response.request_id}, Status code: {response.status_code}, 
-                            error code: {response.code}, error message: {response.message}")
+            raise HTTPError('Request id: %s, Status code: %s, error code: %s, error message: %s' % (
+                            response.request_id, response.status_code,
+                            response.code, response.message
+                        ))
 
     return chat, history