public function setCreatorOwner(string $creator_owner = "T") : CNabuDataObject
    {
        if ($creator_owner === null) {
            throw new ENabuCoreException(
                    ENabuCoreException::ERROR_NULL_VALUE_NOT_ALLOWED_IN,
                    array("\$creator_owner")
            );
        }
        $this->setValue('nb_user_group_type_creator_owner', $creator_owner);
        
        return $this;
    }