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

Code before:
                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(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:
                break
        else:
            raise ExtractorError(f'Cannot identify player {player_url!r}')
        return id_m.group('id')

    def _load_player(self, video_id, player_url, fatal=True):
        player_id = self._extract_player_info(player_url)
        if player_id not in self._code_cache:
            code = self._download_webpage(
                player_url, video_id, fatal=fatal,
                note='Downloading player ' + player_id,
                errnote=f'Download of {player_url} failed',
                headers=self._generate_webpage_headers(player_url))
            if code:
                self._code_cache[player_id] = code
        return self._code_cache.get(player_id)

    def _extract_signature_function(self, video_id, player_url, example_sig):
        player_id = self._extract_player_info(player_url)

        # Read from filesystem cache
        func_id = f'js_{player_id}_{self._signature_cache_id(example_sig)}'
        assert os.path.basename(func_id) == func_id

        self.write_debug(f'Extracting signature function {func_id}')
        cache_spec, code = self.cache.load('youtube-sigfuncs', func_id), None

        if not cache_spec:
            code = self._load_player(video_id, player_url)
        if code:
            res = self._parse_sig_js(code)
            test_string = ''.join(map(chr, range(len(example_sig))))
            cache_spec = [ord(c) for c in res(test_string)]
            self.cache.store('youtube-sigfuncs', func_id, cache_spec)

        return lambda s: ''.join(s[i] for i in cache_spec)

    def _print_sig_code(self, func, example_sig):

Review comment (suggestion):
```suggestion
                headers=self._webpage_headers)
```

Code after:
                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(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:
                break
        else:
            raise ExtractorError(f'Cannot identify player {player_url!r}')
        return id_m.group('id')

    def _load_player(self, video_id, player_url, fatal=True):
        player_id = self._extract_player_info(player_url)
        if player_id not in self._code_cache:
            code = self._download_webpage(
                player_url, video_id, fatal=fatal,
                note='Downloading player ' + player_id,
                errnote=f'Download of {player_url} failed',
                headers=self._generate_webpage_headers())
            if code:
                self._code_cache[player_id] = code
        return self._code_cache.get(player_id)

    def _extract_signature_function(self, video_id, player_url, example_sig):
        player_id = self._extract_player_info(player_url)

        # Read from filesystem cache
        func_id = f'js_{player_id}_{self._signature_cache_id(example_sig)}'
        assert os.path.basename(func_id) == func_id

        self.write_debug(f'Extracting signature function {func_id}')
        cache_spec, code = self.cache.load('youtube-sigfuncs', func_id), None

        if not cache_spec:
            code = self._load_player(video_id, player_url)
        if code:
            res = self._parse_sig_js(code)
            test_string = ''.join(map(chr, range(len(example_sig))))
            cache_spec = [ord(c) for c in res(test_string)]
            self.cache.store('youtube-sigfuncs', func_id, cache_spec)

        return lambda s: ''.join(s[i] for i in cache_spec)

    def _print_sig_code(self, func, example_sig):