public function getCatalog($nb_catalog)
    {
        $retval = false;

        if (is_object($nb_catalog) && !($nb_catalog instanceof CNabuDataObject)) {
            throw new ENabuCoreException(
                ENabuCoreException::ERROR_UNEXPECTED_PARAM_CLASS_TYPE,
                array('$nb_catalog', get_class($nb_catalog))
            );
        }

        if ($nb_catalog !== null) {
            $nb_catalog_id = nb_getMixedValue($nb_catalog, NABU_CATALOG_FIELD_ID);
            if (is_numeric($nb_catalog_id) || nb_isValidGUID($nb_catalog_id)) {
                $retval = $this->nb_catalog_list->getItem($nb_catalog_id);
            } elseif ($nb_catalog_id !== null && $nb_catalog_id !== false) {
                throw new ENabuCoreException(
                    ENabuCoreException::ERROR_UNEXPECTED_PARAM_VALUE,
                    array('$nb_catalog', print_r($nb_catalog, true))
                );
            }
        }

        return $retval;
    }