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<?php

/**
 * Class TNW_Salesforce_Model_Observer
 */
class TNW_Salesforce_Model_Observer
{
 
    public function invoiceSetObject(Varien_Event_Observer $observer) {
		/** 
		 * @var Varien_Object $_sf_object 
		 * 
		 * Example:
		 * object(Varien_Object)[2]
		 *   protected '_data' => 
		 *     array (size=1)
		 *       'object_type' => string 'invoice' (length=7)
		 *     ...
		 */
		$_sf_object = $observer->getData('sf_object');

        // Your custom code
    }
 
}