'@param request: When supplied, I will use namespace aliases
that match those in this request.  I will also check to
make sure I do not respond with attributes that were not
requested.
@type request: L{FetchRequest}
@param update_url: By default, C{update_url} is taken from the
request.  But if you do not supply the request, you may set
the C{update_url} here.
@type update_url: str'

def __init__(self, request=None, update_url=None):

    AXKeyValueMessage.__init__(self)
    self.update_url = update_url
    self.request = request
