/**
  * Fetch list of plugin email observers
  * @param $pluginName
  * @return mixed|null
  */
 private function _getPluginObserversList($pluginName)
 {
     try {
         $pluginReflection = new Zend_Reflection_Class(Tools_Factory_PluginFactory::createPlugin($pluginName));
     } catch (Exceptions_SeotoasterPluginException $spe) {
         return null;
     }
     if ($pluginReflection->hasProperty(Tools_Mail_Watchdog::OBSERVER_LIST_PROP)) {
         return $pluginReflection->getStaticPropertyValue(Tools_Mail_Watchdog::OBSERVER_LIST_PROP);
     }
     return null;
 }