def _clone_tracks(self, new_event):
attrs = get_simple_column_attrs(Track)
for old_track in self.old_event.tracks:
track = Track()
track.populate_from_attrs(old_track, attrs)
track.acl_entries = clone_principals(TrackPrincipal, old_track.acl_entries)
track.track_group = self._track_group_map.get(old_track.track_group, None)
new_event.tracks.append(track)
self._track_map[old_track] = track
