Example on main API Notebook page is not working

[fermelone]

When running the last item:

// The song's details will be in the response body.
songs.songs.songId('3').get();

When executing "Let's access a particular song:" I get a 404 error:

$3=	
Object {"body": "Cannot GET /mocks/n8/songs/3", "status": 404, "headers": Object}
body: "Cannot GET /mocks/n8/songs/3"
headers: Object
status: 404

Thanks