Simplify formats accumulation for f4m/m3u8/smil formats

Now all _extract_*_formats routines return a list

1 files changed, 2 insertions, 4 deletions

diff --git a/youtube_dl/extractor/jwplatform.py b/youtube_dl/extractor/jwplatform.py
index a92adf2b3..8e90d5986 100644
--- a/youtube_dl/extractor/jwplatform.py
+++ b/youtube_dl/extractor/jwplatform.py
@@ -44,10 +44,8 @@ class JWPlatformIE(InfoExtractor):
             source_url = self._proto_relative_url(source['file'])
             source_type = source.get('type') or ''
             if source_type == 'application/vnd.apple.mpegurl':
-                m3u8_formats = self._extract_m3u8_formats(
-                    source_url, video_id, 'mp4', 'm3u8_native', fatal=False)
-                if m3u8_formats:
-                    formats.extend(m3u8_formats)
+                formats.extend(self._extract_m3u8_formats(
+                    source_url, video_id, 'mp4', 'm3u8_native', fatal=False))
             elif source_type.startswith('audio'):
                 formats.append({
                     'url': source_url,