Solve cannot import name 'anchor_generator_pb2'

According to the tf official document git clone, execute the protos step, but found that there is no one. After downloading according to the tutorial,
execute the protos and execute
python -m pip install --use-feature=2020-resolver .
the running code. The error is still reported.

cannot import name 'anchor_generator_pb2'

Finally, it was found that it was a problem with python -m pip, and the problem was solved
by using itpip install .