cleanIds example

  protected function getFromStorage(array $ids = NULL) {
    $entities = [];

    if (!empty($ids)) {
      // Sanitize IDs. Before feeding ID array into buildQuery, check whether       // it is empty as this would load all entities.       $ids = $this->cleanIds($ids);
    }

    if ($ids === NULL || $ids) {
      // Build and execute the query.       $query_result = $this->buildQuery($ids)->execute();
      $records = $query_result->fetchAllAssoc($this->idKey);

      // Map the loaded records into entity objects and according fields.       if ($records) {
        $entities = $this->mapFromStorageRecords($records);
      }
    }