fix: fix bug for 3D data inversion

[tomsail]

This PR is to fix issue #43

I had to add the black tools for formatting / linting.

I'll comment below for the on the important changes.

[tomsail]

The fix I provided should work for reading the data.

I just had to reshape for the:

• lazy mode
• eager mode

However, since we reshape when read the data, we'd need to reshape when exporting the data too..
And I'm not sure I did my job well there (in selafin.write)

All the tests pass but one:
the comparison between the original Selafin and the one we wrote

[tomsail]

I think I have cracked it