Ryu package:

Change

```
from eventlet.wsgi import ALREADY_HANDLED
```

to

```
import eventlet.wsgi
ALREADY_HANDLED = getattr(eventlet.wsgi, "ALREADY_HANDLED", None)
```

Or use two virtual env

Pre-commit:

If you install QoA4ML from source, install the dev version or all version (editable or not) by:
```
# editable
pip install -e ".[dev]"
# non-editable
pip install ".[dev]"
```
Installing dev version will automatically have pre-commit, then, install pre-commit:
```
pre-commit install
```
Pre-commit failed: pre-commit can't automatically add new update to staging so you have to manually stage the file update from pre-commit
Run pre-commit for all files, not just staging:
```
pre-commit run --all-files
```