public function isForPostType(string $post_type = ''): bool
    {
        if (!$this->Wp->is_admin) {
            return false; // Not applicable.
        } elseif (!($current = $this->current())) {
            return false; // Nope.
        } elseif (!($current_post_type = $this->currentPostType())) {
            return false; // Nope.
        } elseif (!in_array($current, ['post-new.php', 'post.php', 'edit.php', 'edit-tags.php'], true)) {
            return false; // Nope.
        }
        if (!$post_type) {
            return true; // Simple check.
        }
        if ($post_type[0] === '/') {
            $regex = $post_type; // Treat as regex.
        } else {
            $regex = '/^'.$this->c::wregxFrag($post_type, '_').'$/ui';
        }
        return (bool) preg_match($regex, $current_post_type);
    }