Unable to extract Initial JS player signature function name

[7rikka]

Hey,I meet a error when download youtube video --> https://www.youtube.com/watch?v=lG_yxnLp0r8
and some error occured
my youtue-dl version is 2018.09.01
how to fix it?

[youtube] lG_yxnLp0r8: Downloading webpage
[youtube] lG_yxnLp0r8: Downloading video info webpage
[youtube] lG_yxnLp0r8: Downloading js player vfloFxffr
ERROR: Signature extraction failed: Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/youtube_dl/extractor/youtube.py", line 1210, in _decrypt_signature
video_id, player_url, s
File "/usr/local/lib/python3.6/dist-packages/youtube_dl/extractor/youtube.py", line 1121, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/local/lib/python3.6/dist-packages/youtube_dl/extractor/youtube.py", line 1182, in _parse_sig_js
jscode, 'Initial JS player signature function name', group='sig')
File "/usr/local/lib/python3.6/dist-packages/youtube_dl/extractor/common.py", line 972, in _search_regex
raise RegexNotFoundError('Unable to extract %s' % _name)
youtube_dl.utils.RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
(caused by RegexNotFoundError('Unable to extract \x1b[0;34mInitial JS player signature function name\x1b[0m; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.',)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.