public function itemAtIndexInPriority($index, $priority = null)
{
if ($priority === null) {
$priority = $this->getDefaultPriority();
}
$priority = (string) round(TPropertyValue::ensureFloat($priority), $this->_p);
return !isset($this->_d[$priority]) ? false : (isset($this->_d[$priority][$index]) ? $this->_d[$priority][$index] : false);
}