public function getIContactByKey(string $key)
    {
        if (!is_string($key) || strlen($key) === 0) {
            throw new ENabuCoreException(
                ENabuCoreException::ERROR_UNEXPECTED_PARAM_VALUE,
                array('$key', print_r($key, true))
            );
        }

        return $this->nb_icontact_list->getItem($key, CNabuIContactList::INDEX_KEY);
    }