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

Code before:
            str)
        shelf_url = urljoin('https://www.youtube.com', ep)
        if shelf_url:
            # Skipping links to another channels, note that checking for
            # endpoint.commandMetadata.webCommandMetadata.webPageTypwebPageType == WEB_PAGE_TYPE_CHANNEL
            # will not work
            if skip_channels and '/channels?' in shelf_url:
                return
            title = self._get_text(shelf_renderer, 'title')
            yield self.url_result(shelf_url, video_title=title)
        # Shelf may not contain shelf URL, fallback to extraction from content
        yield from self._shelf_entries_from_content(shelf_renderer)

    def _playlist_entries(self, video_list_renderer):
        for content in video_list_renderer['contents']:
            if not isinstance(content, dict):
                continue
            renderer = content.get('playlistVideoRenderer') or content.get('playlistPanelVideoRenderer')
            if not isinstance(renderer, dict):
                continue
            video_id = renderer.get('videoId')
            if not video_id:
                continue
            yield self._extract_video(renderer)

    def _extract_lookup_view_model(self, view_model):
        content_id = view_model.get('contentId')
        if not content_id:
            return
        if view_model.get('contentType') not in ('LOCKUP_CONTENT_TYPE_PLAYLIST', 'LOCKUP_CONTENT_TYPE_PODCAST'):
            self.report_warning(
                f'Unsupported lookup view model content type "{view_model.get("contentType")}"{bug_reports_message()}', only_once=True)
            return
        return self.url_result(
            f'https://www.youtube.com/playlist?list={content_id}', ie=YoutubeTabIE, video_id=content_id,
            title=traverse_obj(view_model, (
                'metadata', 'lockupMetadataViewModel', 'title', 'content', {str})),
            thumbnails=self._extract_thumbnails(view_model, (
                'contentImage', 'collectionThumbnailViewModel', 'primaryThumbnail', 'thumbnailViewModel', 'image'), final_key='sources'))

    def _rich_entries(self, rich_grid_renderer):
        if lookup_view_model := traverse_obj(rich_grid_renderer, ('content', 'lockupViewModel', {dict})):
            if entry := self._extract_lookup_view_model(lookup_view_model):
                yield entry
            return
        renderer = traverse_obj(
            rich_grid_renderer,
            ('content', ('videoRenderer', 'reelItemRenderer', 'playlistRenderer', 'shortsLockupViewModel'), any)) or {}
        video_id = renderer.get('videoId')
        if video_id:
            yield self._extract_video(renderer)

Review comment (refactor):
```suggestion
    def _extract_lockup_view_model(self, view_model):
```

Code after:
            str)
        shelf_url = urljoin('https://www.youtube.com', ep)
        if shelf_url:
            # Skipping links to another channels, note that checking for
            # endpoint.commandMetadata.webCommandMetadata.webPageTypwebPageType == WEB_PAGE_TYPE_CHANNEL
            # will not work
            if skip_channels and '/channels?' in shelf_url:
                return
            title = self._get_text(shelf_renderer, 'title')
            yield self.url_result(shelf_url, video_title=title)
        # Shelf may not contain shelf URL, fallback to extraction from content
        yield from self._shelf_entries_from_content(shelf_renderer)

    def _playlist_entries(self, video_list_renderer):
        for content in video_list_renderer['contents']:
            if not isinstance(content, dict):
                continue
            renderer = content.get('playlistVideoRenderer') or content.get('playlistPanelVideoRenderer')
            if not isinstance(renderer, dict):
                continue
            video_id = renderer.get('videoId')
            if not video_id:
                continue
            yield self._extract_video(renderer)

    def _extract_lockup_view_model(self, view_model):
        content_id = view_model.get('contentId')
        if not content_id:
            return
        content_type = view_model.get('contentType')
        if content_type not in ('LOCKUP_CONTENT_TYPE_PLAYLIST', 'LOCKUP_CONTENT_TYPE_PODCAST'):
            self.report_warning(
                f'Unsupported lockup view model content type "{content_type}"{bug_reports_message()}', only_once=True)
            return
        return self.url_result(
            f'https://www.youtube.com/playlist?list={content_id}', ie=YoutubeTabIE, video_id=content_id,
            title=traverse_obj(view_model, (
                'metadata', 'lockupMetadataViewModel', 'title', 'content', {str})),
            thumbnails=self._extract_thumbnails(view_model, (
                'contentImage', 'collectionThumbnailViewModel', 'primaryThumbnail', 'thumbnailViewModel', 'image'), final_key='sources'))

    def _rich_entries(self, rich_grid_renderer):
        if lockup_view_model := traverse_obj(rich_grid_renderer, ('content', 'lockupViewModel', {dict})):
            if entry := self._extract_lockup_view_model(lockup_view_model):
                yield entry
            return
        renderer = traverse_obj(
            rich_grid_renderer,
            ('content', ('videoRenderer', 'reelItemRenderer', 'playlistRenderer', 'shortsLockupViewModel'), any)) or {}
        video_id = renderer.get('videoId')
        if video_id: