Get parentView from within Ember JS liquid-fire v0.19.3 custom transition

I want to get reference to the parentView of this.oldElement or this.newElement from within my custom transition. Previously, I would simply be able to callthis.parentView but I believe this private API has been phased out.

Something like this:

/* app/transitions/my-cool-transition.js */
export default function(foo, bar, _opts) {
  var parentView = this.parentView; //FIX: This doesn't work anymore

  if(parentView) {
    // Do stuff...
  } 

  stop(this.oldElement);
  return Ember.RSVP.Promise.all([
    animate(...),
    animate(...)
  ]).then(function() {
    // Finished, now manipulate the parent view again
    if (parentView) {
      // Do stuff...
    }
  });
});