/**
* Return the highest available praxis scores in this collection.
*/
public function max_praxis()
{
$tests = new self($this->student);
$children = array();
foreach (array('PRXR', 'PRXW', 'PRXM') as $code) {
$test = $this->max($code);
if ($test) {
$children[] = $test;
}
}
$tests->add_children_bare($children);
return $tests;
}
