Split a list into two parts based on a filter?

[Roy Smith]

In article <mailman.2992.1370904643.3114.python-list at python.org>,
 Roel Schroeven <roel at roelschroeven.net> wrote:

> new_songs, old_songs = [], []
> [(new_songs if s.is_new() else old_songs).append(s) for s in songs]

Thanks kind of neat, thanks.

I'm trying to figure out what list gets created and discarded.  I think 
it's [None] * len(songs).