bzr invocation fails after today bionic upgrade

[Mateusz Korniak]

$ BZR_DEBUG=1 bzr
Traceback (most recent call last):
  File "/usr/bin/bzr", line 109, in <module>
    import bzrlib.commands
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 49, in <module>
    from bzrlib.hooks import Hooks
  File "/usr/lib/python2.7/dist-packages/bzrlib/hooks.py", line 95, in <module>
    known_hooks.register_lazy_hook(_hook_module, _hook_attribute, _hook_class)
  File "/usr/lib/python2.7/dist-packages/bzrlib/hooks.py", line 46, in register_lazy_hook
    self.register_lazy((hook_module_name, hook_member_name),
AttributeError: 'KnownHooksRegistry' object has no attribute 'register_lazy'

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: bzr 2.7.0+bzr6622-10
ProcVersionSignature: Ubuntu 4.15.0-34.37-generic 4.15.18
Uname: Linux 4.15.0-34-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.3
Architecture: amd64
CurrentDesktop: KDE
Date: Thu Sep 20 11:26:24 2018
PackageArchitecture: all
SourcePackage: bzr
UpgradeStatus: Upgraded to bionic on 2018-09-04 (15 days ago)

[Mateusz Korniak (matkor76)]

False alarm, after restarting, bzr/ qbzr works as expected.