private static function deleteOldFeedItems(
        AdWordsServices $adWordsServices,
        AdWordsSession $session,
        $feedItemIds,
        $feedId
    ) {
        if (count($feedItemIds) === 0) {
            return;
        }

        $feedItemService = $adWordsServices->get($session, FeedItemService::class);

        $operations = [];
        foreach ($feedItemIds as $feedItemId) {
            $feedItem = new FeedItem();
            $feedItem->setFeedId($feedId);
            $feedItem->setFeedItemId($feedItemId);

            $operation = new FeedItemOperation();
            $operation->setOperand($feedItem);
            $operation->setOperator(Operator::REMOVE);
            $operations[] = $operation;
        }

        printf(
            "Deleting %d old feed items from feed ID %d...\n",
            count($feedItemIds),
            $feedId
        );

        return $feedItemService->mutate($operations);
    }