def denied_response(self, req):
if not hasattr(req, '<STR_LIT>'):<EOL><INDENT>req.credentials_valid = None<EOL><DEDENT>if req.remote_user or req.credentials_valid:<EOL><INDENT>return HTTPForbidden(request=req)<EOL><DEDENT>else:<EOL><INDENT>return HTTPUnauthorized(request=req)<EOL><DEDENT>
Returns a standard WSGI response callable with the status of 403 or 401
        depending on whether the REMOTE_USER is set or not.