[pbs] Fix multi part videos extraction

youtube_dl/extractor/pbs.py

@@ -366,8 +366,12 @@ class PBSIE(InfoExtractor):
                 webpage, 'upload date', default=None))
 
             # tabbed frontline videos
-            tabbed_videos = re.findall(
-                r'<div[^>]+class="videotab[^"]*"[^>]+vid="(\d+)"', webpage)
+            MULTI_PART_REGEXES = (
+                r'<div[^>]+class="videotab[^"]*"[^>]+vid="(\d+)"',
+                r'<a[^>]+href=["\']#video-\d+["\'][^>]+data-coveid=["\'](\d+)',
+            )
+            for p in MULTI_PART_REGEXES:
+                tabbed_videos = re.findall(p, webpage)
                 if tabbed_videos:
                     return tabbed_videos, presumptive_id, upload_date