class My_Module_Model_Observer { public function myObserver($observer) { $transport = $observer->getTransport(); // Do something with the transport object } }In this example, the $observer variable is an instance of the Varien_Event_Observer class. We then use the getTransport method to retrieve the data that was passed along with the event. We can then manipulate this data as needed. The Varien_Event_Observer class is part of the Magento core library, which is included in the app/code/core/Mage directory of a Magento installation.