Sample code from github.jcabi.com does not compile on version 0.23

There are several compilation problems with the code sample from the main page:

This code does not pass Qulice checks either, I expect it to be compliant.

Moreover, I'd like to see one more example on the main page. Not only how to post a comment in new issue, but also for example how to access some particular pull request and add label there or whatever else what will give better starting point.