Downloading the ISO image...
Traceback (most recent call last):
  File "/usr/bin/unity8-lxc-setup", line 191, in <module>
    urlretrieve(ISO_URL.replace("ARCH", architecture), iso_filename, dlProgress)
  File "/usr/lib/python3.4/urllib/request.py", line 178, in urlretrieve
    with contextlib.closing(urlopen(url, data)) as fp:
  File "/usr/lib/python3.4/urllib/request.py", line 153, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.4/urllib/request.py", line 461, in open
    response = meth(req, response)
  File "/usr/lib/python3.4/urllib/request.py", line 571, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python3.4/urllib/request.py", line 499, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.4/urllib/request.py", line 433, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.4/urllib/request.py", line 579, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 404: Not Found