Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 102, in _get_https_content_py3
    lp_page = urllib.request.urlopen(request, cafile=LAUNCHPAD_PPA_CERT)
  File "/usr/lib/python3.5/urllib/request.py", line 163, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.5/urllib/request.py", line 472, in open
    response = meth(req, response)
  File "/usr/lib/python3.5/urllib/request.py", line 582, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python3.5/urllib/request.py", line 510, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.5/urllib/request.py", line 444, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.5/urllib/request.py", line 590, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 404: Not Found

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 327, in get_ppa_info
    ret = get_ppa_info_from_lp(user, ppa)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 92, in get_ppa_info_from_lp
    return get_info_from_lp(lp_url)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 88, in get_info_from_lp
    return _get_https_content_py3(lp_url)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 108, in _get_https_content_py3
    raise PPAException("Error reading %s: %s" % (lp_url, reason), e)
softwareproperties.ppa.PPAException: 'Error reading https://launchpad.net/api/1.0/~djcj/+archive/ubuntu/vlc-stable: Not Found'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 393, in shortcut_handler
    return PPAShortcutHandler(shortcut)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 356, in __init__
    info = get_ppa_info(self.shortcut)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 339, in get_ppa_info
    _get_suggested_ppa_message(user, ppa))
softwareproperties.shortcuts.ShortcutException: Cannot add PPA: 'ppa:~djcj/ubuntu/vlc-stable'.
The user named '~djcj' has no PPA named 'ubuntu/vlc-stable'
Please choose from the following available PPAs:
 * 'aegisub':  Aegisub
 * 'hybrid':  Hybrid
 * 'mediainfo':  MediaInfo
 * 'mkvtoolnix':  MKVtoolnix
 * 'nightingale':  Nightingale Media Player
 * 'screenfetch':  screenFetch
Error: 'ppa:djcj/vlc-stable' invalid