Drop Python 2 Support

[jhamman]

Drops support for Python 2. Closes #393.

TODO:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/tutorial.rst
• Changes documented in docs/release.rst
• Docs build locally (e.g., run tox -e docs)
• AppVeyor and Travis CI passes
• Test coverage is 100% (Coveralls passes)

[jeromekelleher]

Thanks for doing this @jhamman! We dropped Python 2 support in tskit in this PR, which might be useful in outlining the steps required. In particular, pyupgrade seems really useful.

[pep8speaks]

Hello @jhamman! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2019-10-18 20:13:27 UTC

[jhamman]

Thanks @jeromekelleher - I've implemented the following steps

1. changed setup.py to include python_requires
2. removed Python 2 special cases (e.g. if PY2: ...)
3. run pyupgrade
4. run isort -rc --atomic . (helped with step 5)
5. removed zarr.compat, imports to py3 modules

Tests are passing locally for me but we'll wait to see what coveralls/travis reports. I also need to add a note in docs/release.rst

[jhamman]

@zarr-developers/core-devs - just pinging everyone on this. Luckily, we don't have any merge conflicts yet but it would still be good to get this reviewed and merged before things get messy.

[jhamman]

@zarr-developers/core-devs - one more ping here. This needs a review.

[alimanfoo]

Looks good to me! Only noticed one line in the tox config file which could go as well.

[alimanfoo]

Thank you Joe, feels like a weight lifted to see this one go in :-)

…

On Sat, 19 Oct 2019, 05:10 Joe Hamman, ***@***.***> wrote: Merged #470 <#470> into master. — You are receiving this because you are on a team that was mentioned. Reply to this email directly, view it on GitHub <#470?email_source=notifications&email_token=AAFLYQRLXEO5I243FHYYVB3QPKCENA5CNFSM4ILMQDB2YY3PNVWWK3TUL52HS4DFWZEXG43VMVCXMZLOORHG65DJMZUWGYLUNFXW5KTDN5WW2ZLOORPWSZGOUKDYFTI#event-2726789837>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFLYQSKSV3YPZ2F6FBNSBTQPKCENANCNFSM4ILMQDBQ> .