vyos@server:~$ show dhcpv6 server leases 
Traceback (most recent call last):
  File "/usr/libexec/vyos/op_mode/dhcp.py", line 438, in <module>
    res = vyos.opmode.run(sys.modules[__name__])
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/vyos/opmode.py", line 263, in run
    res = func(**args)
          ^^^^^^^^^^^^
  File "/usr/libexec/vyos/op_mode/dhcp.py", line 265, in _wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/libexec/vyos/op_mode/dhcp.py", line 322, in show_server_leases
    return _get_formatted_server_leases(lease_data, family=family)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/libexec/vyos/op_mode/dhcp.py", line 175, in _get_formatted_server_leases
    end =  _utc_to_local(end).strftime('%Y/%m/%d %H:%M:%S')
           ^^^^^^^^^^^^^^^^^^
  File "/usr/libexec/vyos/op_mode/dhcp.py", line 47, in _utc_to_local
    return datetime.fromtimestamp((datetime.fromtimestamp(utc_dt) - datetime(1970, 1, 1)).total_seconds())
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'NoneType' object cannot be interpreted as an integer
vyos@server:~$