// AddIndexerIfNotPresent adds the index function with the name into the cache indexer if not present
func AddIndexerIfNotPresent(indexer cache.Indexer, indexName string, indexFunc cache.IndexFunc) error {
	indexers := indexer.GetIndexers()
	if _, ok := indexers[indexName]; ok {
		return nil
	}
	return indexer.AddIndexers(cache.Indexers{indexName: indexFunc})