Track.get_analysis() failure

I didn't upload the song, I got the ID from the track_from_id() example at: http://echonest.github.io/pyechonest/track.html.

I also tried with a number of ID's I got from the following query:

songs = song.search(style='rock',
                    max _tempo=150,
                    min _tempo=30,
                    results=100)

song _ids = [a _song.id for a _song in songs]

and got the same results.