Repository: yt-dlp/yt-dlp
File: yt_dlp/extractor/nova.py (Python)

Code before:
                    drm_formats.append(format_dict)
                    continue
                format_url = url_or_none(format_dict.get('src'))
                format_type = format_dict.get('type')
                ext = determine_ext(format_url)
                if (format_type == 'application/x-mpegURL'
                        or format_id == 'HLS' or ext == 'm3u8'):
                    formats.extend(self._extract_m3u8_formats(
                        format_url, video_id, 'mp4',
                        entry_protocol='m3u8_native', m3u8_id='hls',
                        fatal=False))
                elif (format_type == 'application/dash+xml'
                      or format_id == 'DASH' or ext == 'mpd'):
                    formats.extend(self._extract_mpd_formats(
                        format_url, video_id, mpd_id='dash', fatal=False))
                else:
                    formats.append({
                        'url': format_url,
                    })

        player = self._parse_json(
            self._search_regex(
                r'player:\s*(?P<json>.*?)}\s*;?\s*</script>',
                webpage, 'player', default='{}', flags=re.DOTALL, group='json'), video_id, fatal=False)
        if player:
            for src in traverse_obj(player, ('lib', 'source', 'sources'), default=[]):
                process_format_list(src)
            duration = int_or_none(traverse_obj(player, ('sourceInfo', 'duration')))
        if not formats and not drm_formats:
            player = self._parse_json(
                self._search_regex(
                    (r'(?:(?:replacePlaceholders|processAdTagModifier).*?:\s*)?(?:replacePlaceholders|processAdTagModifier)\s*\(\s*(?P<json>{.*?})\s*\)(?:\s*\))?\s*,',
                     r'Player\.init\s*\([^,]+,(?P<cndn>\s*\w+\s*\?)?\s*(?P<json>{(?(cndn).+?|.+)})\s*(?(cndn):|,\s*{.+?}\s*\)\s*;)'),
                    webpage, 'player', default='{}', group='json'), video_id, fatal=False)
            if player:
                for format_id, format_list in player['tracks'].items():
                    process_format_list(format_list, format_id)
                duration = int_or_none(player.get('duration'))
            else:
                # Old path, not actual as of 08.04.2020
                bitrates = self._parse_json(
                    self._search_regex(
                        r'(?s)(?:src|bitrates)\s*=\s*({.+?})\s*;', webpage, 'formats'),
                    video_id, transform_source=js_to_json)

                QUALITIES = ('lq', 'mq', 'hq', 'hd')
                quality_key = qualities(QUALITIES)

                for format_id, format_list in bitrates.items():
                    if not isinstance(format_list, list):
                        format_list = [format_list]

Review comment (suggestion):
branching with `...` in traversal will always return a list
```suggestion
            for src in traverse_obj(player, ('lib', 'source', 'sources', ...)):
```

Code after:
                    has_drm = True
                    continue
                format_url = url_or_none(format_dict.get('src'))
                format_type = format_dict.get('type')
                ext = determine_ext(format_url)
                if (format_type == 'application/x-mpegURL'
                        or format_id == 'HLS' or ext == 'm3u8'):
                    formats.extend(self._extract_m3u8_formats(
                        format_url, video_id, 'mp4',
                        entry_protocol='m3u8_native', m3u8_id='hls',
                        fatal=False))
                elif (format_type == 'application/dash+xml'
                      or format_id == 'DASH' or ext == 'mpd'):
                    formats.extend(self._extract_mpd_formats(
                        format_url, video_id, mpd_id='dash', fatal=False))
                else:
                    formats.append({
                        'url': format_url,
                    })

        player = self._search_json(
            r'player:', webpage, 'player', video_id, fatal=False, end_pattern=r';\s*</script>')
        if player:
            for src in traverse_obj(player, ('lib', 'source', 'sources', ...)):
                process_format_list(src)
            duration = traverse_obj(player, ('sourceInfo', 'duration', {int_or_none}))
        if not formats and not has_drm:
            # older code path, in use before August 2023
            player = self._parse_json(
                self._search_regex(
                    (r'(?:(?:replacePlaceholders|processAdTagModifier).*?:\s*)?(?:replacePlaceholders|processAdTagModifier)\s*\(\s*(?P<json>{.*?})\s*\)(?:\s*\))?\s*,',
                     r'Player\.init\s*\([^,]+,(?P<cndn>\s*\w+\s*\?)?\s*(?P<json>{(?(cndn).+?|.+)})\s*(?(cndn):|,\s*{.+?}\s*\)\s*;)'),
                    webpage, 'player', group='json'), video_id)
            if player:
                for format_id, format_list in player['tracks'].items():
                    process_format_list(format_list, format_id)
                duration = int_or_none(player.get('duration'))

        if not formats and has_drm:
            self.report_drm(video_id)

        title = self._og_search_title(
            webpage, default=None) or self._search_regex(
            (r'<value>(?P<title>[^<]+)',
             r'videoTitle\s*:\s*(["\'])(?P<value>(?:(?!\1).)+)\1'), webpage,
            'title', group='value')
        thumbnail = self._og_search_thumbnail(
            webpage, default=None) or self._search_regex(
            r'poster\s*:\s*(["\'])(?P<value>(?:(?!\1).)+)\1', webpage,
            'thumbnail', fatal=False, group='value')
        duration = int_or_none(self._search_regex(