Add legacy support (Python 3.7 & 3.8) in Sterzo

[tensorturtle]

importlib.resources.files in sterzo.py was newly introduced in Python 3.9.
I needed to use this library on Python 3.8, so I implemented a version check to use the correct importlib API. More info at python docs

The only side effect is that the sterzo-challenge-codes.dat file had to be moved out of the data directory.

[tensorturtle]

I tested the change on Python 3.8 and Python 3.10 with success.

[zacharyedwardbull]

Hey! Thanks for spotting this lack of compatibility with Python 3.7/3.8 and suggesting this fix. It looks good, I've just left a few comments.

[zacharyedwardbull]

I think we can keep the data directory, we just need to add __init__.py to make it a Python package

[tensorturtle]

Do you mean putting a __init__.py to the data directory like so?

├── pycycling
       ├── sterzo.py
       ├── data
       │   ├── __init__.py
       │   └── sterzo-challenge-codes.dat

[zacharyedwardbull]

Yep! Can be completely empty I believe.

[zacharyedwardbull]

Is there a reason not to use importlib.resources.open_binary?

[tensorturtle]

Will be using that instead.

[zacharyedwardbull]

Can we refactor this to remove the duplication of these lines?

[tensorturtle]

Putting sterzo-challenges-codes.dat into a data directory with __init__.py does not work:

Using:

with importlib.resources.open_binary(__package__, 'data/sterzo-challenge-codes.dat') as fp:

Throws:

  File "/home/tensorturtle/Repos/pycycling/pycycling/sterzo.py", line 34, in _activate_steering_measurements
    with importlib.resources.open_binary(__package__, 'data/sterzo-challenge-codes.dat') as fp:
  File "/usr/lib/python3.10/importlib/resources.py", line 42, in open_binary
    resource = _common.normalize_path(resource)
  File "/usr/lib/python3.10/importlib/_common.py", line 34, in normalize_path
    raise ValueError(f'{path!r} must be only a file name')
ValueError: 'data/sterzo-challenge-codes.dat' must be only a file name

I think this limitation is what the docs are referring to when it says:

The main drawback of these functions is that they do not support directories: they assume all resources are located directly within a package.
https://docs.python.org/3/library/importlib.resources.html#deprecated-functions

[zacharyedwardbull]

Since we've created a subpackage, you need to add a import pycycling.data to the imports then replace __package__ with pycycling.data in the call.

[tensorturtle]

Thank you for guiding me. Please see latest commit

[tensorturtle]

I tested both branches

[tensorturtle]

Fix #28