Generally preferred python version

[buckleyc]

I was looking at Empyrial/empyrial.py, with the intention of cleaning up the code. In general, I mean items such as proper and consistent indenting, cleaner comments, consistent spacing, etc.
To that end, there are some general issues surrounding some conditionals that I would want to clean up. But I want to be sure that the group would be comfortable with this. I generally use python 3.9 (currently running 3.9.5 & 3.9.6). Any code modification would be usable from 3.7 and later.
I was wondering if anyone is trying to use or maintain compatibility with python versions earlier than 3.7.

[santoshlite]

Hi @buckleyc,

Thank you for contributing 😸 . I think this should be fine for most users here. So far, no user has raised an issue related to a python version problem. 3.7 should be fine!

[buckleyc]

Okay; with that in mind, I did a large rewrite to empyrial.py today, and have committed these. Please note, that there should be no functional impact, and there were actually a number of bug fixes. You should see the Pull Request now. Cheers.

[santoshlite]

Ok, I'll check that and merge it, thank you so much for this contribution!

[santoshlite]

Hi @buckleyc, I changed the version but it gave me an error as you can see here: https://colab.research.google.com/drive/1NrCZmIZP9oTUlSGufacQrQWxuCzGxJ9M?usp=sharing

[buckleyc]

I am seeing something similar. Unsure of which change that would have caused this. Looking into this now.

[buckleyc]

I may have found the issue. Working on it.

[buckleyc]

Okay - this should be fixed. The major issue was that I had omitted the 'not' in the conditional 'if self.rebalance is not None', which made everything after it fail. I still think this needs to be handled better. Particularly the conditional 'if self.rebalance is not None:' (now) starting at line 90; so much use of the word 'rebalance'. I also cleaned up the handling for when the optimizer is called from the dict.
Please give it a try so we can confirm it is working as you expect.

[santoshlite]

That worked! Thankss