protected function getIndexerByItem($indexingConfigurationName, TypoScriptConfiguration $configuration)
    {
        $indexerClass = $configuration->getIndexQueueIndexerByConfigurationName($indexingConfigurationName);
        $indexerConfiguration = $configuration->getIndexQueueIndexerConfigurationByConfigurationName($indexingConfigurationName);

        $indexer = GeneralUtility::makeInstance($indexerClass, /** @scrutinizer ignore-type */ $indexerConfiguration);
        if (!($indexer instanceof Indexer)) {
            throw new \RuntimeException(
                'The indexer class "' . $indexerClass . '" for indexing configuration "' . $indexingConfigurationName . '" is not a valid indexer. Must be a subclass of ApacheSolrForTypo3\Solr\IndexQueue\Indexer.',
                1260463206
            );
        }

        return $indexer;
    }