I found solution by accident here. Code:
use Gedmo\Sluggable\Util as Sluggable;
$string = 'My own text!';
$slug = Sluggable\Urlizer::urlize($string, '-');
if(empty($slug)) // if $string is like '=))' or 'トライアングル・サービス' an empty slug will be returned, that causes troubles and throws no exception
echo 'error, empty slug!!!';
else
echo $slug;