public function removeEntry($entryId, $language = null)
    {
        $entryId = (string)$entryId;
        foreach ($this->entries as $languageKey => $entries) {
            if ($language && $language !== $languageKey) {
                continue;
            }
            if (isset($this->entries[$languageKey][$entryId])) {
                unset($this->entries[$languageKey][$entryId]);
            }
        }
        return $this;
    }