Proxy authentication required

[gervaz]

Hi all,
I've got to download some web pages but I'm behind a proxy. So far
this is what I've used without any successful result receiving the
error: "urllib.error.HTTPError: HTTP Error 407: Proxy Authentication
Required ( The ISA Server requires auth
orization to fulfill the request. Access to the Web Proxy filter is
denied.  )":

hc = urllib.request.HTTPCookieProcessor()
hp = urllib.request.ProxyHandler({"http": "10.242.38.251:80",
"username": "domain\username", "password": "password"})
opener = urllib.request.build_opener(hc, hp)
urllib.request.urlopen("http://www.google.it/")

Any suggestion?

Thanks,

Mattia