diff --git a/yt_dlp/extractor/digitalconcerthall.py b/yt_dlp/extractor/digitalconcerthall.py
index c891ad0a6..3813a51fe 100644
--- a/yt_dlp/extractor/digitalconcerthall.py
+++ b/yt_dlp/extractor/digitalconcerthall.py
@@ -86,7 +86,7 @@ class DigitalConcertHallIE(InfoExtractor):
                 })
 
             m3u8_url = traverse_obj(
-                stream_info, ('channel', lambda x: x.startswith('vod_mixed'), 'stream', 0, 'url'), get_all=False)
+                stream_info, ('channel', lambda k, _: k.startswith('vod_mixed'), 'stream', 0, 'url'), get_all=False)
             formats = self._extract_m3u8_formats(m3u8_url, video_id, 'mp4', 'm3u8_native', fatal=False)
             self._sort_formats(formats)