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

Code before:
            'url': 'https://www.youtube.com/shorts/BGQWPY4IigY',
            'only_matching': True,
        },
    ]

    @classmethod
    def suitable(cls, url):
        from ..utils import parse_qs

        qs = parse_qs(url)
        if qs.get('list', [None])[0]:
            return False
        return super(YoutubeIE, cls).suitable(url)

    def __init__(self, *args, **kwargs):
        super(YoutubeIE, self).__init__(*args, **kwargs)
        self._code_cache = {}
        self._player_cache = {}

    def _extract_player_url(self, *ytcfgs, webpage=None):
        for ytcfg in ytcfgs:
            player_url = traverse_obj(
                ytcfg, 'PLAYER_JS_URL', ('WEB_PLAYER_CONTEXT_CONFIGS', ..., 'jsUrl'),
                get_all=False, expected_type=compat_str)
            if player_url:
                break
        if not player_url:
            return None
        if player_url.startswith('//'):
            player_url = 'https:' + player_url
        elif not re.match(r'https?://', player_url):
            player_url = compat_urlparse.urljoin(
                'https://www.youtube.com', player_url)
        return player_url

    def _download_player_url(self, video_id, fatal=False):
        res = self._download_webpage(
            'https://www.youtube.com/iframe_api',
            note='Downloading iframe API JS', video_id=video_id, fatal=fatal)
        if res:
            player_version = self._search_regex(
                r'player\\?/([0-9a-fA-F]{8})\\?/', res, 'player version', fatal=fatal)
            if player_version:
                return f'https://www.youtube.com/s/player/{player_version}/player_ias.vflset/en_US/base.js'

    def _signature_cache_id(self, example_sig):
        """ Return a string representation of a signature """
        return '.'.join(compat_str(len(part)) for part in example_sig.split('.'))

    @classmethod
    def _extract_player_info(cls, player_url):

Review comment (suggestion):
```suggestion
        player_url = traverse_obj(
            ytcfgs, (..., 'PLAYER_JS_URL'), (..., 'WEB_PLAYER_CONTEXT_CONFIGS', ..., 'jsUrl'),
            get_all=False, expected_type=compat_str)
```

unless `ytcfgs` is lazy

Code after:
            'url': 'https://www.youtube.com/shorts/BGQWPY4IigY',
            'only_matching': True,
        },
    ]

    @classmethod
    def suitable(cls, url):
        from ..utils import parse_qs

        qs = parse_qs(url)
        if qs.get('list', [None])[0]:
            return False
        return super(YoutubeIE, cls).suitable(url)

    def __init__(self, *args, **kwargs):
        super(YoutubeIE, self).__init__(*args, **kwargs)
        self._code_cache = {}
        self._player_cache = {}

    def _extract_player_url(self, *ytcfgs, webpage=None):
        player_url = traverse_obj(
            ytcfgs, (..., 'PLAYER_JS_URL'), (..., 'WEB_PLAYER_CONTEXT_CONFIGS', ..., 'jsUrl'),
            get_all=False, expected_type=compat_str)
        if not player_url:
            return
        if player_url.startswith('//'):
            player_url = 'https:' + player_url
        elif not re.match(r'https?://', player_url):
            player_url = compat_urlparse.urljoin(
                'https://www.youtube.com', player_url)
        return player_url

    def _download_player_url(self, video_id, fatal=False):
        res = self._download_webpage(
            'https://www.youtube.com/iframe_api',
            note='Downloading iframe API JS', video_id=video_id, fatal=fatal)
        if res:
            player_version = self._search_regex(
                r'player\\?/([0-9a-fA-F]{8})\\?/', res, 'player version', fatal=fatal)
            if player_version:
                return f'https://www.youtube.com/s/player/{player_version}/player_ias.vflset/en_US/base.js'

    def _signature_cache_id(self, example_sig):
        """ Return a string representation of a signature """
        return '.'.join(compat_str(len(part)) for part in example_sig.split('.'))

    @classmethod
    def _extract_player_info(cls, player_url):
        for player_re in cls._PLAYER_INFO_RE:
            id_m = re.search(player_re, player_url)
            if id_m: