validInsertCase example

    private function validateLanguages(array $mapping, PreWriteValidationEvent $event): void
    {
        $inserts = [];
        $duplicates = [];
        $deletions = [];
        $updates = [];

        foreach ($mapping as $id => $channel) {
            if (isset($channel['inserts'])) {
                if (!$this->validInsertCase($channel)) {
                    $inserts[$id] = $channel['new_default'];
                }

                $duplicatedIds = $this->getDuplicates($channel);

                if ($duplicatedIds) {
                    $duplicates[$id] = $duplicatedIds;
                }
            }

            if (isset($channel['deletions']) && !$this->validDeleteCase($channel)) {