code: public function generate()
      {
          $this->getFields();
          $result = [];
          if (!empty($this->_settings['title'])) {
              $result[] = Html::beginTag('fieldset');
              $result[] = Html::tag('legend', $this->_settings['title']);
          }
          $result[] = $this->grid->generate();
          if (!empty($this->_settings['title'])) {
              $result[] = Html::endTag('fieldset');
          }
  
          return implode("\n", $result);
      }
docs: [[@doctodo method_description:generate]].
  
  @return unknown