public static function addFields()
    {
        $tags = ['text', 'text*', 'email', 'email*', 'url', 'url*', 'tel', 'tel*'];
        foreach ($tags as $tag) {
            //We have to remove tags before replacing them.
            wpcf7_remove_form_tag($tag);
        }
        wpcf7_add_form_tag($tags, [self::class, 'addCustomFields'], true);
    }