From 3151cee03f1ee105157ff2fa1f56803c21e6f283 Mon Sep 17 00:00:00 2001
From: Dmitry Vinnik <vinnik.dmitry07@gmail.com>
Date: Tue, 7 Apr 2020 13:26:36 +0300
Subject: [PATCH] Update youtube.py

---
 youtube_dl/extractor/youtube.py | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 081b710df..33b93f3ca 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -2184,9 +2184,9 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             video_alt_title = video_creator = None
 
         def extract_meta(field):
-            return re.search(
+            return self._search_regex(
                 r'<h4[^>]+class="title"[^>]*>\s*%s\s*</h4>\s*<ul[^>]*>\s*<li>(.+?)</li>\s*' % field,
-                video_webpage).group(1)
+                video_webpage, field, default=None)
 
         def extract_meta_url(list_elem_content:str):
             if list_elem_content.endswith('</a>'):
@@ -2194,8 +2194,18 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             else:
                 return None, list_elem_content
 
-        music_relative_url, track = extract_meta_url(extract_meta('Song'))
-        artist_relative_url, artist = extract_meta_url(extract_meta('Artist'))
+        song_elem_content = extract_meta('Song')
+        if song_elem_content:
+            music_relative_url, track = extract_meta_url(song_elem_content)
+        else:
+            music_relative_url = track = None
+
+        artist_elem_content = extract_meta('Artist')
+        if artist_elem_content:
+            artist_relative_url, artist = extract_meta_url(artist_elem_content)
+        else:
+            artist_relative_url = artist = None
+
         album = extract_meta('Album')
 
         # Youtube Music Auto-generated description