<type 'exceptions.AttributeError'>: 'Transaction' object has no attribute 'gettest'

Binary package hint: aptdaemon

I got the following traceback:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 963, in simulate
    status_path)
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1034, in _simulate_helper
    self._get_broken_details(trans))
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1270, in _get_broken_details
    or_msg += trans.gettest("but it is a virtual package")
AttributeError: 'Transaction' object has no attribute 'gettest'

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: aptdaemon 0.41+bzr595-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-5.32-generic 2.6.38-rc6
Uname: Linux 2.6.38-5-generic i686
Annotation: Applying software changes failed
Architecture: i386
Date: Sat Mar 12 10:00:45 2011
DesktopFile: /usr/share/aptdaemon/aptdaemon.desktop
ExecutablePath: /usr/sbin/aptd
SourcePackage: aptdaemon
Title: <type 'exceptions.AttributeError'>: 'Transaction' object has no attribute 'gettest'
TransactionDepends: [[], [], [], [], [], [], []]
TransactionErrorCode: error-unknown
TransactionKwargs: {}
TransactionLocale: de_DE.UTF8
TransactionOutput:

TransactionPackages: [[], [], [], [], [dbus.String(u'network-manager'), dbus.String(u'network-manager-gnome')], []]
TransactionRole: role-commit-packages
UpgradeStatus: Upgraded to natty on 2011-03-09 (2 days ago)