function toXML($event_code = null, $hpr_datatypes = true, $encoding = "utf-8")
 {
     $name = $this->getXMLName();
     $dom = CHPrim21MessageXML::getEventType($event_code);
     $root = $dom->addElement($dom, $name);
     $dom->addNameSpaces($name);
     return $this->_toXML($root, $hpr_datatypes, $encoding);
 }
 static function handleEvent($data = array(), CEchangeHprim21 $exchange_hpr, CHPrim21MessageXML $dom_evt, CHPrim21Acknowledgment $ack)
 {
     $data = array_merge($data, $dom_evt->getContentNodes());
     $object = new CSejour();
     return $dom_evt->handle($ack, $object, $data);
 }