public function DefaultLocale()
    {
        // Return explicit default locale
        if ($this->DefaultLocaleID) {
            $locale = Locale::getCached()->byID($this->DefaultLocaleID);
            if ($locale) {
                return $locale;
            }
        }

        // Use IsGlobalDefault if this is a member of this locale, or the first in the list of children
        $locales = Locale::getCached()->filter('DomainID', $this->ID);
        return $locales->filter('IsGlobalDefault', 1)->first()
            ?: $locales->first();
    }