private function exportProjectUgroups(Project $project, SimpleXMLElement $into_xml)
 {
     $this->logger->debug("Exporting project's static ugroups");
     $ugroups = $this->ugroup_manager->getStaticUGroups($project);
     if (empty($ugroups)) {
         return;
     }
     $ugroups_node = $into_xml->addChild('ugroups');
     foreach ($ugroups as $ugroup) {
         $this->logger->debug("Current static ugroups: " . $ugroup->getName());
         $ugroup_node = $ugroups_node->addChild('ugroup');
         $ugroup_node->addAttribute('name', $ugroup->getNormalizedName());
         $ugroup_node->addAttribute('description', $ugroup->getDescription());
         $members_node = $ugroup_node->addChild('members');
         foreach ($ugroup->getMembers() as $member) {
             $this->user_xml_exporter->exportUser($member, $members_node, 'member');
         }
     }
     $rng_path = realpath(dirname(__FILE__) . '/../xml/resources/ugroups.rng');
     $this->xml_validator->validate($ugroups_node, $rng_path);
 }