Update app.py

app.py

@@ -339,7 +339,7 @@ def get_generation_progress():
     Get the current progress of answer generation.
     """
     if not processing_status["is_processing"] and processing_status["progress"] == 0:
-        return "Not started", None
+        return "Not started"
     
     if processing_status["is_processing"]:
         progress = processing_status["progress"]