error when fetching image using s3

[marsha97]

>>> from urllib.request import urlopen
>>> urlopen("https://assets-s3.web.com/watermarks/some_image.png")
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    urlopen("https://assets-s3.web.com/watermarks/some_image.png")
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 532, in open
    response = meth(req, response)
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 642, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 570, in error
    return self._call_chain(*args)
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/local/opt/python/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 650, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden

looks like user-agent problem