Return the filename of the bundled bundle

def get_url(self, version=None):
        """
        Return the filename of the bundled bundle
        """
        if self.fixed_bundle_url:
            return self.fixed_bundle_url
        return '%s.%s.%s' % (os.path.join(self.bundle_url_root, self.bundle_filename), version or self.get_version(), self.bundle_type)