LGTM.com - false positive - Use of the return value of a procedure

**Description of the false positive**

This is idiomatic Python and shouldn't raise a warning, even when the result of `main` is always `None`.
```python
if __name__ == "__main__":
sys.exit(main())
```
See:
https://docs.python.org/fr//3/library/__main__.html#packaging-considerations

> Since the call to `main` is wrapped in [`sys.exit()`](https://docs.python.org/fr//3/library/sys.html#sys.exit), the expectation is that your function will return some value acceptable as an input to [`sys.exit()`](https://docs.python.org/fr//3/library/sys.html#sys.exit); typically, an integer or `None` (which is implicitly returned if your function does not have a return statement).
>
> By proactively following this convention ourselves, our module will have the same behavior when run directly (i.e. `python3 echo.py`) as it will have if we later package it as a console script entry-point in a pip-installable package.

**URL to the alert on the project page on LGTM.com**

https://lgtm.com/projects/g/lamyj/odil/snapshot/00e9ad1ac34f7c310a264e3953e32d24b765cd2f/files/examples/python/convert.py?sort=name&dir=ASC&mode=heatmap#xf881ca92aa273c47:1