@symptoms = $session->getEventExplainedBy( $object, $event, $flag )
The getEventExplainedBy() function returns the list of symptoms that are explained by the specified impact event.
The $flag is a boolean that indicates whether the event impact tree is to be walked during the processing of the request.
@list = $session->getEventExplainedBy( "Router::gw1", "DownImpact", 1);