public function getSiteRoles(bool $force = false) : CNabuSiteRoleList
    {
        if ($this->nb_site_role_list->isEmpty() || $force) {
            $this->nb_site_role_list->clear();
            $this->nb_site_role_list->merge(CNabuSiteRole::getSiteRolesForSite($this));
        }

        return $this->nb_site_role_list;
    }