diff --git a/backend/ydl_pool.py b/backend/ydl_pool.py
index 6d85a30..8a78e64 100644
--- a/backend/ydl_pool.py
+++ b/backend/ydl_pool.py
@@ -155,7 +155,9 @@ class Downloader:
             ydl.params['playlist_items'] = ','.join(str(i) for i in playlist_items)
 
         ret = ydl.download(url)
-        del ydl.params['playlist_items']
+
+        if playlist_items:
+            del ydl.params['playlist_items']
 
         return ret