public function getTasks()
    {
        $tasks = [];
        for ($i = 0, $size = count($this->children); $i < $size; $i++) {
            $tsk = $this->children[$i];
            if ($tsk instanceof Task) {
                // note: we're copying objects here!
                $tasks[] = clone $tsk;
            }
        }

        return $tasks;
    }