Assigning playWhenReady wrongly in codelab-00

In PlayerActivity.releasePlayer(), inside player?.run block playWhenReady is assigning wrong:

// Inside run block 'this' refer to player and current context is also player
// so we can use:
// this@PlayerActivity.playWhenReady = playWhenReady
// instead of below line.
**playWhenReady = this.playWhenReady**

Start in codelab-00 at PlayerActivity.releasePlayer(), specifically the player?.run block and its playWhenReady assignment. Check the receiver and enclosing activity reference, then verify that the saved player state is assigned to the intended property; done means the assignment matches the issue's requested behavior.

Written by the indexing model from the issue text.