code: public function render($outputDestination = null)
      {
          if ($outputDestination == 'php://output') {
              $outputDestination = null;
          }
  
          $libraryName = Settings::getChartRenderer();
          if ($libraryName === null) {
              return false;
          }
  
          // Ensure that data series values are up-to-date before we render
          $this->refresh();
  
          $renderer = new $libraryName($this);
  
          return $renderer->render($outputDestination);
      }
docs: Render the chart to given file (or stream).
  
  @param string $outputDestination Name of the file render to
  
  @return bool true on success