$ cd <espnet_root>
$ pip install -e ".[doc]"
$ pip install -U flake8-docstrings

# in ci/test_flake8.sh

# you can improve poorly written docstrings from here
flake8_black_list="\
espnet/__init__.py
espnet/asr/asr_mix_utils.py
espnet/asr/asr_utils.py
espnet/asr/chainer_backend/asr.py
...
"

# --extend-ignore for wip files for flake8-docstrings
flake8 --extend-ignore=D test utils doc ${flake8_black_list}

# white list of files that should support flake8-docstrings
flake8 espnet --exclude=${flake8_black_list//$'\n'/,}

$ cd <espnet_root>
$ ./ci/doc.sh