Let the parent SWF get the event for the child SwF (AS3)

In AS3, if the parent SWF loads a child SWF, and the child SWF loads a txt file, how does the parent SWF know when the child SWF loads the txt file?

Code in the child SWF:

var urlrequest:urlrequest=new urlrequest ("A.txt");
var loader:urlloader=new urlloader ();
Loader.load (URLRequest);

Loader.addeventlistener (event.complete,com);
function COM (evt) {
Dispatchevent (New Event ("Go"));
}

Output is loadtxt.swf

Code in the parent SWF:

var urlrequest:urlrequest=new urlrequest ("loadtxt.swf");
var loader:loader=new loader ();
Loader.load (URLRequest);
Loader.contentLoaderInfo.addEventListener (event.complete,com);
function COM (evt) {
Evt.target.content.addEventListener ("Go", Testhandler)

}
AddChild (loader);
function Testhandler (evt) {
Trace (1);
}

This will be heard by the parent SWF when the child SWF load TXT completes.