Return the URL redirect to. Keyword arguments from the
        URL pattern match generating the redirect request
        are provided as kwargs to this method.

def get_redirect_url(self, request, **kwargs):
        """
        Return the URL redirect to. Keyword arguments from the
        URL pattern match generating the redirect request
        are provided as kwargs to this method.
        """
        if self.url:
            url = self.url % kwargs
            args = request.META.get('QUERY_STRING', '')
            if args and self.query_string:
                url = "%s?%s" % (url, args)
            return url
        else:
            return None