In node, you can define a package.json. Then define a `script` block as following:

```
"scripts": {
    "start": "concurrently -k -r -s first \"yarn test:watch\" \"yarn open:src\" \"yarn lint:watch\"",
  },

```

So in root directory, I can just do `yarn start` to run `concurrently -k -r -s first \"yarn test:watch\" \"yarn open:src\" \"yarn lint:watch\"`

What is the equivalent of that in Python 3? If I want to have a script called `python test` to run `python -m unittest discover -v`