Upload app.py

app.py

@@ -15,10 +15,10 @@ def run(url, mode):
 
     if url != last_url:
         last_url = url
-        if os.path.exists(last_video):
+        if last_video and os.path.exists(last_video):
             os.remove(last_video)
         last_video = None
-        if os.path.exists(last_audio):
+        if last_audio and os.path.exists(last_audio):
             os.remove(last_audio)
         last_audio = None
         last_chat = None