How to tell someone there's a bug in code writed in playground?

Question

Just like what i write in title

Answer 1

At upper right corner of the codes, you can see "n comments" is written. Click/tap on that. If there's no comments previously, then there'll be a "+" button (green). Tap on that and leave your comment :)
* n is the number of comments.

Answer 2

He wants to submit a playground bug

Answer 3

Write to them:
[e-mail]

Answer 4

Tim G thanks
I do what you say~

Answer 5

You can leave comments.

Answer 6

Sorry but where can i leave a comment?
There's no button to do so