protected static function get_target_locales()
    {
        // if locales are explicitly set, use these
        if (is_array(self::config()->locales)) {
            return (array)self::config()->locales;
            // otherwise check the allowed locales. If these have been set, use these
        } else if (is_array(Translatable::get_allowed_locales())) {
            return (array)Translatable::get_allowed_locales();
        }

        // last resort is to take the existing content languages
        return array_keys(Translatable::get_existing_content_languages());
    }