CakeEventManager::instance PHP Method

    public static function instance($manager = null)
    {
        if ($manager instanceof CakeEventManager) {
            static::$_generalManager = $manager;
        }
        if (empty(static::$_generalManager)) {
            static::$_generalManager = new CakeEventManager();
        }
        static::$_generalManager->_isGlobal = true;
        return static::$_generalManager;
    }

 public function changeStatus(Model $Model, $status, $id = null, $force = false)
 {
     if ($id === null) {
         $id = $Model->getID();
     }
     if ($id === false) {
         return false;
     }
     $force = true;
     $Model->id = $id;
     if (!$Model->exists()) {
         throw new NotFoundException();
     }
     if ($force !== true) {
         $modelData = $Model->read();
         if ($modelData[$Model->alias]['status'] === $status) {
             CakeLog::write(LOG_WARNING, __d('webshop', 'The status of %1$s with id %2$d is already set to %3$s. Not making a change', strtolower(Inflector::humanize(Inflector::underscore($Model->name))), $id, $status), array('webshop'));
             return false;
         }
     } else {
         CakeLog::write(LOG_WARNING, __d('webshop', 'Status change of %1$s with id %2$d is being forced to %3$s', strtolower(Inflector::humanize(Inflector::underscore($Model->name))), $id, $status), array('webshop'));
     }
     $Model->saveField('status', $status);
     CakeLog::write(LOG_INFO, __d('webshop', 'Changed status of %1$s with id %2$d to %3$s', strtolower(Inflector::humanize(Inflector::underscore($Model->name))), $id, $status), array('webshop'));
     $eventData = array();
     $eventData[Inflector::underscore($Model->name)]['id'] = $id;
     $eventData[Inflector::underscore($Model->name)]['status'] = $status;
     $overallEvent = new CakeEvent($Model->name . '.statusChanged', $this, $eventData);
     $specificEvent = new CakeEvent($Model->name . '.statusChangedTo' . Inflector::camelize($status), $this, $eventData);
     CakeEventManager::instance()->dispatch($overallEvent);
     CakeEventManager::instance()->dispatch($specificEvent);
     return true;
 }