public function getUser($force = false)
    {
        if ($this->nb_user === null || $force) {
            $this->nb_user = null;
            if ($this instanceof CNabuDataObject &&
                $this->contains(NABU_USER_FIELD_ID) &&
                $this->isValueNumeric(NABU_USER_FIELD_ID)
            ) {
                $nb_user = new CNabuUser($this->getValue(NABU_USER_FIELD_ID));
                if ($nb_user->isFetched()) {
                    $this->nb_user = $nb_user;
                }
            }
        }

        return $this->nb_user;
    }