protected function normalizeAccessKey($key, $index_name = null)
	{
		if (empty($index_name)) {
			@list($index_name, $key) = explode('.', $key);

			if (empty($key)) {
				$key = $index_name;
				$index_name = 'default';
			}
		}

		return [$index_name, $key];
	}