Using the tween class within a class and .onMotionFinished

trying to get the .onMotionFinished method of my tween instance within my class to have access to class variables and methods:

var t1:Tween = new Tween(myClip, "_alpha", None.easeNone, 0, 100, 1, true);
trace("this is a var from the class: "+classVar);

right now the ‘classVar’ variable from the class comes back as undefined. the tween is outside of the class scope correct? How can i make the tween instance have access to the class scope so i can call a method from the class and access class variables?