Builds the URL path fragment for this route.

def path(self, args, kw):
        """Builds the URL path fragment for this route."""
        params = self._pop_params(args, kw)
        if args or kw:
            raise InvalidArgumentError("Extra parameters (%s, %s) when building path for %s" % (args, kw, self.template))
        return self.build_url(**params)