code: public function render(array $classes = [], $autoEscape = null)
      {
          $divOpen = '<div class="' . $this->divClass . '">';
          $divClose = '</div>';
          $hasMessages = false;
  
          foreach ($this->classes as $namespace => $namespaceClasses) {
              $namespaceClasses = ArrayUtils::merge($namespaceClasses, $classes);
              if ($this->getFlashMessengerHelper()->getPluginFlashMessenger()->hasCurrentMessages($namespace)) {
                  $hasMessages = true;
                  $divOpen .= $this->getFlashMessengerHelper()->renderCurrent($namespace, $namespaceClasses, $autoEscape);
                  $this->getFlashMessengerHelper()->getPluginFlashMessenger()->clearCurrentMessagesFromNamespace($namespace);
              } elseif ($this->getFlashMessengerHelper()->getPluginFlashMessenger()->hasMessages($namespace)) {
                  $hasMessages = true;
                  $divOpen .= $this->getFlashMessengerHelper()->render($namespace, $namespaceClasses, $autoEscape);
              }
          }
  
          return $hasMessages ? $divOpen . $divClose : '';
      }
docs: Render All Messages
  
  @param  array $classes
  @param  null|bool $autoEscape
  @return string