code: public function generate(ReportSummary $reportSummary)
      {
          if (!\extension_loaded('dom')) {
              throw new \RuntimeException('Cannot generate report! `ext-dom` is not available!');
          }
  
          $dom = new \DOMDocument('1.0', 'UTF-8');
          $checkstyles = $dom->appendChild($dom->createElement('checkstyle'));
  
          foreach ($reportSummary->getChanged() as $filePath => $fixResult) {
              /** @var \DOMElement $file */
              $file = $checkstyles->appendChild($dom->createElement('file'));
              $file->setAttribute('name', $filePath);
  
              foreach ($fixResult['appliedFixers'] as $appliedFixer) {
                  $error = $this->createError($dom, $appliedFixer);
                  $file->appendChild($error);
              }
          }
  
          $dom->formatOutput = true;
  
          return $reportSummary->isDecoratedOutput() ? OutputFormatter::escape($dom->saveXML()) : $dom->saveXML();
      }
docs: {@inheritdoc}