packageSack.returnNewestByName() appears to be broken in yum-3.0.1-2.fc6.

Reproducer is in upgradecheck.py CVS rev 1.28,
http://cvs.fedora.redhat.com/viewcvs/upgradecheck/upgradecheck.py?root=fedora&rev=1.28&view=auto
(line numbers could be a bit off):

Traceback (most recent call last):
  File "./upgradecheck.py", line 257, in ?
    main()
  File "./upgradecheck.py", line 162, in main
    for l in solvers[dist].pkgSack.returnNewestByName():
  File "/usr/lib/python2.4/site-packages/yum/packageSack.py", line 298, in
returnNewestByName
    bestofeach.addList(self._computeAggregateListResult("returnNewestByName", name))
  File "/usr/lib/python2.4/site-packages/yum/packageSack.py", line 650, in addList
    self.addPackage(pkgobj)
  File "/usr/lib/python2.4/site-packages/yum/packageSack.py", line 474, in
addPackage
    repoid = obj.returnSimple('repoid')
AttributeError: 'list' object has no attribute 'returnSimple'

One workaround which I'll apply to upgradecheck.py is to use
returnNewestByNameArch() instead of returnNewestByName() (and eliminate the
related inner loop), but it'd be nice to have returnNewestByName() fixed.  It
works as expected in yum-2.6.1-0.fc5.