public function add($selector, $context = NULL)
{
$result = $this->spawn($this);
if (isset($context)) {
$result->push($this->spawn($context)->find($selector));
} elseif (is_object($selector) || is_string($selector) && substr(ltrim($selector), 0, 1) === '<') {
$result->push($this->build()->getContentNodes($selector));
} else {
$result->push($this->find($selector));
}
$result->_nodes = $result->unique($result->_nodes);
return $result;
}