public function addPaginator($rows = 25, $options = null, $class = null)
    {
        // add only once
        // @todo decide, maybe we should destroy and recreate to keep last one
        if ($this->paginator) {
            return $this->paginator;
        }

        $this->paginator = $this->add($class ?: $this->paginator_class, $options);
        /** @type Paginator $this->paginator */
        $this->paginator->setRowsPerPage($rows);

        return $this->paginator;
    }