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

Code before:
            if not next_url:
                break

    def _real_extract(self, url):
        collection_slug = self._match_id(url)
        channel = self._call_api(
            f'https://content.api.nebula.app/content/{collection_slug}/?include=lessons',
            collection_slug, note='Retrieving channel')

        if channel.get('type') == 'class':
            entries = self._generate_class_entries(channel)
        elif channel.get('type') == 'podcast_channel':
            entries = self._generate_podcast_entries(channel['id'], collection_slug)
        else:
            entries = self._generate_playlist_entries(channel['id'], collection_slug)

        return self.playlist_result(
            entries=entries,
            playlist_id=collection_slug,
            playlist_title=channel.get('title'),
            playlist_description=channel.get('description'))


class NebulaSeasonIE(NebulaBaseIE):
    IE_NAME = 'nebula:seasons'
    _VALID_URL = rf'{_BASE_URL_RE}/(?P<sn>\w+)/?season/(?P<sid>\d+)'
    _TESTS = [{
        'url': 'https://nebula.tv/jetlag/season/15',
        'info_dict': {
            'id': 'jetlag_15',
        },
        'playlist_count': 6,
    }, {
        'url': 'https://nebula.tv/jetlag/season/14',
        'info_dict': {
            'id': 'jetlag_14',
        },
        'playlist_mincount': 6,
    }, {
        'url': 'https://nebula.tv/jetlag/season/10',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        season_name, season_id = self._match_valid_url(url).group('sn', 'sid')
        video_id = f'{season_name}_{season_id}'
        data = self._call_api(f'https://content.api.nebula.app/content/{season_name}/season/{season_id}', video_id)
        if not data.get('episodes'):
            raise ExtractorError('No Episodes Found')
        return self.playlist_result((
            self.url_result(f'https://nebula.tv/{traverse_obj(ep, ("video", "app_path"))}')

Review comment (suggestion):
- the slash should not be optional
- use more obvious group names
- `[\w-]+` instead of `\w+`, per the channel name pattern above

```suggestion
    _VALID_URL = rf'{_BASE_URL_RE}/(?P<series>[\w-]+)/season/(?P<season_number>\d+)'
```

Code after:
            if not next_url:
                break

    def _real_extract(self, url):
        collection_slug = self._match_id(url)
        channel = self._call_api(
            f'https://content.api.nebula.app/content/{collection_slug}/?include=lessons',
            collection_slug, note='Retrieving channel')

        if channel.get('type') == 'class':
            entries = self._generate_class_entries(channel)
        elif channel.get('type') == 'podcast_channel':
            entries = self._generate_podcast_entries(channel['id'], collection_slug)
        else:
            entries = self._generate_playlist_entries(channel['id'], collection_slug)

        return self.playlist_result(
            entries=entries,
            playlist_id=collection_slug,
            playlist_title=channel.get('title'),
            playlist_description=channel.get('description'))


class NebulaSeasonIE(NebulaBaseIE):
    IE_NAME = 'nebula:season'
    _VALID_URL = rf'{_BASE_URL_RE}/(?P<series>[\w-]+)/season/(?P<season_number>\d+)'
    _TESTS = [{
        'url': 'https://nebula.tv/jetlag/season/15',
        'info_dict': {
            'id': 'jetlag_15',
            'title': 'Tag: All Stars',
            'description': 'md5:5aa5b8abf3de71756448dc44ffebb674',
        },
        'playlist_count': 8,
    }, {
        'url': 'https://nebula.tv/jetlag/season/14',
        'info_dict': {
            'id': 'jetlag_14',
            'title': 'Snake',
            'description': 'md5:6da9040f1c2ac559579738bfb6919d1e',
        },
        'playlist_count': 8,
    }]

    def _build_url_result(self, item):
        url = (
            traverse_obj(item, ('share_url', {url_or_none}))
            or urljoin('https://nebula.tv/', item.get('app_path'))
            or f'https://nebula.tv/videos/{item["slug"]}')
        return self.url_result(
            smuggle_url(url, {'id': item['id']}),