public function endStack()
    {
        $stacks = array_pop($this->stacks);

        $stacks = (array) $stacks;

        foreach ($stacks as $block) {
            $content = $this->pushes[$block];

            if (is_null($content)) {
                $content = $this->tintin->getCompiler()->compile(ob_get_clean());
            }

            $this->pushes[$block] = trim($content, "\n");
        }
    }