'Returns a 401 response with a small bit on
what OAuth is, and where to learn more about it.
When this was written, browsers did not understand
OAuth authentication on the browser side, and hence
the helpful template we render. Maybe some day in the
future, browsers will take care of this stuff for us
and understand the 401 with the realm we give it.'

def challenge(self):

    response = HttpResponse()
    response.status_code = 401
    for (k, v) in oauth.build_authenticate_header(realm=self.realm).iteritems():
        response[k] = v
    response.content = '\n                                                Unable    to    authenticate.\n                                                Make    sure    you    use    oAuth    1.0    authentication    and    a    valid    consumer    key.\n                                                    '
    return response
