public function findLastIndex() {
		if (func_num_args() == 1) {
			$callback = func_get_arg(0);
		} else {
			$query = func_get_arg(0);
			$callback = func_get_arg(1);
		}
		
		$index = func_num_args() == 1 ? $this->findLast($callback) : $this->findLast($query, $callback);
		if ($index !== null) {
			$index = $this->indexOf($index);
		}
	
		return $index;
	}