AttributeError: 'NoneType' object has no attribute 'group'

[rapierbit]

I figure this has to be simple issue, but I'm not finding a reference to it anywhere.

I'm trying to use pafy on a Raspberry Pi 4, originally booted with Buster from the summer (8/20?) but apt-get upgraded since.

Then sudo apt-get install python3-pafy.

I can't do the simplest example in the documentation without the error cited on the subject line:

import pafy
url = "https://www.youtube.com/watch?v=bMt47wvK6u0"
video = pafy.new(url)

And then the error gets thrown (shown below). It's unclear to me which offending call is returning an object of 'NoneType' that then further has no attribute 'group'.

I note that the latest pafy is 0.5.5 but apt-get installs 0.5.2-2. I'm not a big user of pip but would that be my recommended approach here? Anyone know if this is a known issue, or am I missing something else?

======================================================

Traceback (most recent call last):
File "<pyshell#2>", line 1, in
video = pafy.new(url)
File "/usr/lib/python3/dist-packages/pafy/pafy.py", line 122, in new
return Pafy(url, basic, gdata, size, callback, ydl_opts)
File "/usr/lib/python3/dist-packages/pafy/backend_internal.py", line 42, in _$
super(InternPafy, self).init(*args, kwargs)
File "/usr/lib/python3/dist-packages/pafy/backend_shared.py", line 95, in __i$
self._fetch_basic()
File "/usr/lib/python3/dist-packages/pafy/backend_internal.py", line 50, in _$
allinfo = get_video_info(self.videoid, self.callback)
File "/usr/lib/python3/dist-packages/pafy/backend_internal.py", line 268, in $
sts = re.search(r'sts"\s:\s(\d+)', embed_webpage).group(1)
AttributeError: 'NoneType' object has no attribute 'group'

[mango16384]

May I ask you that is the problem solved?
I'm also having this issue with pafy 0.5.5 on python 3.6.7

[jankais3r]

This issue is caused by pafy's internal backend being outdated and having troubles with parsing the current YouTube video page. backend_internal.py received last update in November 2018. As mentioned in pafy.py:

youtube-dl not found; you can use the internal backend by setting the environmental variable PAFY_BACKEND to "internal". It is not enabled by default because it is not as well maintained as the youtube-dl backend.

The issue can be solved by installing youtube-dl. You have to install youtube-dl via pip, not via apt.