protected function initUpdateServers()
 {
     if (!$this->package->hasUpdateservers()) {
         return;
     }
     $this->writer->startElement('updateservers');
     foreach ($this->package->getUpdateservers() as $server) {
         if (trim($server->getUrl()) == '') {
             continue;
         }
         $this->writer->startElement('server');
         $this->writeAttributeIfValueNotEmpty('type', $server->getType());
         $this->writeAttributeIfValueNotEmpty('priority', $server->getPriority());
         $this->writeAttributeIfValueNotEmpty('name', $server->getName());
         $this->writer->text($server->getUrl());
         $this->writer->endElement();
     }
     $this->writer->endElement();
 }