public function countFiles()
    {
        $nbFiles = $this->entity->files->count();
        $label = $nbFiles ? 'label-success' : 'label-default';
        $html = [];
        $html[] = '<span class="label '.$label.'">';
        $html[] = $nbFiles;
        $html[] = '</span>';

        return implode("\r\n", $html);
    }