code: public static function setChartRenderer($rendererClass)
      {
          if (!is_a($rendererClass, IRenderer::class, true)) {
              throw new Exception('Chart renderer must implement ' . IRenderer::class);
          }
  
          self::$chartRenderer = $rendererClass;
      }
docs: Identify to PhpSpreadsheet the external library to use for rendering charts.
  
  @param string $rendererClass Class name of the chart renderer
  eg: PhpOffice\PhpSpreadsheet\Chart\Renderer\JpGraph
  
  @throws Exception