How to use the zookeeper.ZOO_SESSION_EVENT function in zookeeper

var lw = function(type, state, p){
	if( type == ZooKeeper.ZOO_CHANGED_EVENT ) {
	    zk.aw_get( path, lw, function() {} );
	} else if( type == ZooKeeper.ZOO_DELETED_EVENT ) {	    
	    // Our sentinal disappeared - this could mean that 
	    // we are now the leader, or it could mean that we
	    // need to watch someone else.
	    zk_election(zk,dir,me,cb);
	} else if( type == ZooKeeper.ZOO_SESSION_EVENT ) {
	    //console.log("Session problem!");
	    // zk will keep our callback around - no need to re-establish.
	} else {
	    console.log( "Unkown type: " + type );
	    throw new Error("Unknown change type");
	} 
    };
    zk.aw_get( path, lw, function() {} );

var lw = function(type, state, p){
	if( type == ZooKeeper.ZOO_CHANGED_EVENT ) {
	    zk.aw_get( path, lw, function() {} );
	} else if( type == ZooKeeper.ZOO_DELETED_EVENT ) {	    
	    // Our sentinal disappeared - this could mean that 
	    // we are now the leader, or it could mean that we
	    // need to watch someone else.
	    election(zk,dir,me);
	} else if( type == ZooKeeper.ZOO_SESSION_EVENT ) {
	    //console.log("Session problem!");
	    // zk will keep our callback around - no need to re-establish.
	} else {
	    console.log( "Unkown type: " + type );
	    //zk.aw_get( path, lw, function() {} );
	} 
    };
    zk.aw_get( path, lw, function() {} );