protected function findParentHook(): string
    {
        if (! $this->hasParent()) {
            return '';
        }

        // Check if parent attribute is attached to a custom post type or another page.
        if (false !== $pos = strpos($this->getParent(), 'post_type=')) {
            // Parent hook is equivalent to the post type slug value.
            return substr($this->getParent(), $pos + 10);
        } elseif ('edit.php' === trim($this->getParent(), '\/?&')) {
            // Parent is the default post post type.
            return 'posts';
        }

        // The current page is attached to another one.
        $abstract = 'page.'.$this->getParent();

        if ($this->ui()->factory()->getContainer()->bound($abstract)) {
            // Parent hook is equivalent to the page menu as lowercase.
            $parent = $this->ui()->factory()->getContainer()->make($abstract);

            return strtolower($parent->getMenu());
        }

        return '';
    }