/**
* Sets (or if param is not specified, resets) the current singleton instance
*
* @param Core_Model_Hooks_Dispatcher $instance - OPTIONAL
* @return Core_Model_Hooks_Dispatcher
*/
public static function setInstance(Engine_Hooks_Dispatcher $instance = null)
{
if (null === $instance) {
$instance = new self();
}
self::$_instance = $instance;
return self::$_instance;
}