code: public function template($template = 'email.volt')
      {
          $this->viewPath = $template;
  
          //if we have params thats means we are using a template
          if (is_array($this->params)) {
              $content = $this->getManager()->setRenderView($this->viewPath, $this->params);
          }
  
          $this->getMessage()->setBody($content, self::CONTENT_TYPE_HTML);
  
          return $this;
      }
docs: view relative to the folder viewsDir (REQUIRED)
  
  @param string $template
  
  @return $this