public function get_gaps()
{
$result = array();
$xpath = new DOMXPath($this->node->ownerDocument);
$xpath->registerNamespace("qti", "http://www.imsglobal.org/xsd/imsqti_v2p0");
$search = $xpath->query("//qti:gap");
foreach ($search as $elem) {
$obj = new Gap($elem, $this);
$obj->validate(null);
array_push($result, $obj);
}
return $result;
}
