Issue with Aggregator and LocalRuntime (cannot import name 'aggregator_pb2')

[alexandrakolosova]

In tutorial "MNIST Example: Workflow API"
at the step of importing LocalRuntime and placement decorators,

from openfl.experimental.workflow.interface import FLSpec, Aggregator, Collaborator
from openfl.experimental.workflow.runtime import LocalRuntime

results in
ImportError: cannot import name 'aggregator_pb2' from 'openfl.experimental.workflow.protocols' (/home/user/openfl/openfl/experimental/workflow/protocols/init.py)

Ubuntu 22.04.5 LTS
Python 3.11.11