vyos@r4# rollback 150
Traceback (most recent call last):
  File "/usr/bin/config-mgmt", line 33, in <module>
    sys.exit(load_entry_point('vyos==1.3.0', 'console_scripts', 'config-mgmt')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/vyos/config_mgmt.py", line 757, in run
    res, rc = func(**args)
              ^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/vyos/config_mgmt.py", line 236, in rollback
    msg = f'Invalid revision number {rev}: must be 0 < rev < {maxrev}'
                                                              ^^^^^^
NameError: name 'maxrev' is not defined
[edit]
vyos@r4#