Can't get hostname from User

[sh1omi]

I tring to get the hostname from the user just like in the docs: http://coffea.readthedocs.io/en/latest/user.html
client.on('message', function (event) { console.log(event.user.getHostname()); });
"event.user.getHostname()" return nothing, and this what I get when I print "event.user":
User { nick: 'sh1omi', network: '0', channels: {}, idle: 0, signon: 2016-09-20T10:08:25.159Z }