Bug/435 open sat data

[JackKelly]

Pull Request

Description

Fixes #435

How Has This Been Tested?

• No
• Yes, unit tests pass
• prepare_ml_data.py runs

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings

[JackKelly]

There are two commits in this PR.

I think the first commit is sufficient.

But the second commit slightly simplifies the code (but isn't strictly necessary to solve this bug!)

[jacobbieker]

Looks good! Thanks for fixing it!

[JackKelly]

Thanks for the quick review, @jacobbieker! Just to double-check: Are you happy for the code to always use xr.open_mfdataset? As far as I can tell, open_mfdataset does "the right thing" even if zarr_path points to a single Zarr (with no wildcards) but I haven't really put it through its paces!

[jacobbieker]

Yeah, I think it's fine!