Update app.py

app.py

@@ -123,7 +123,7 @@ def call_main(purpose, task, history, action_input):
         else:
             history += "observation: unknown action: {}\n".format(line)
             #assert False, "unknown action: {}".format(line)
-            return action_name, action_input, history, task
+            return "UPDATE-TASK", None, history, task
             
     return "MAIN", None, history, task