code: public function renderWidget(array $fields, $customFielsGroup, $documentType='html', array $params = array())
      {
          $resolvedParams = array_merge($this->defaultParams, $params);
          
          return $this->container->get('templating')
              ->render($resolvedParams['layout'], array(
              	'cFGroup' => $customFielsGroup,
              	'cFData' => $fields,
                  'show_empty' => $resolvedParams['show_empty']));
      }
docs: Twig extension that is used to render the value of a custom field group.
  
  The presentation of the value  is influenced by the document type.
  
  @param array $fields The array raw, as stored in the db
  @param CustomFieldsGroud $customFielsGroup The custom field group
  @param string $documentType The type of the document (csv, html)
  @param array $params The parameters for rendering :
  - layout : allow to choose a different layout by default :
  ChillCustomFieldsBundle:CustomFieldsGroup:render.html.twig
  - show_empty : force show empty field
  @return string HTML representation of the custom field group value, as described in
  the CustomFieldInterface. Is HTML safe