Import of attributes fails in Neutron v18 (Rocky)

[busterswt]

When loading neutron-server an error occurs:

Unrecoverable error: please check log for details.: ExtensionsNotFound: Extensions not found: ['route-table']. Related to WARNING neutron.api.extensions [-] Extension file vpcroutetable.py wasn't loaded due to cannot import name attributes.

vpcroutetable.py attempts to import attributes from neutron.api.v2:

from neutron.api.v2 import attributes as attr

attributes.py no longer exists, and methods have moved to neutron_lib. Patched the file like so:

from neutron_lib.api import attributes as attr
#from neutron.api.v2 import attributes as attr

Other extensions, like loadbalancercustomattributes.py, may also have the same issue.