code: public function render ($filename, $vars = array(), $toVar = null)
      {
          $templatePath = $this->templatePath . '/' . $filename . '.' . $this->templateExtension;
  
          if (file_exists($templatePath)) {
  
              $template = file_get_contents($templatePath);
              $output = parent::render($template, array_merge($this->vars, $vars));
  
              if ($toVar) {
                  $this->set($toVar, $output);
              } else {
                  echo $output;
              }
  
          } else {
  
              throw new Exception ("Template '$filename' could not be found.");
  
          }
      }
docs: Render a page
  
  @param string      $filename Filename
  @param array       $vars     Variables
  @param string|null $toVar    If specified, it will save as a variable rather than output
  
  @return void