Traceback (most recent call last):
  File "/usr/lib/ubuntu-release-upgrader/do-partial-upgrade", line 114, in <module>
    controller.doPartialUpgrade()
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeController.py", line 2109, in doPartialUpgrade
    if not self.doPostUpgrade():
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeController.py", line 1487, in doPostUpgrade
    if not self.cache.tryMarkObsoleteForRemoval(pkgname, remove_candidates, self.foreign_pkgs):
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeCache.py", line 241, in wrapper
    res = f(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeCache.py", line 927, in tryMarkObsoleteForRemoval
    if pkgname in self and self[pkgname].section == section:
AttributeError: 'Package' object has no attribute 'section'