Quick noob oop question :)

i have 2 classes, class A and class B

in class A i instantiate class B

in class B i do this:


private var _vLineMask:LineMask;
_vLineMask = new LineMask("v", 0xffffff);
_vLineMask.addEventListener(LineMask.DONE_TRANSITION, transitionDone, false, 0, true);

how can i listen for that event in class A?