Removes the usage of conda._vendor.toolz from constructor

[travishathaway]

This pull request replaces the usage of toolz in the main conda project. In an upcoming conda, release this will be completely removed.

I chose to completely copy over the code from the toolz repository into this one. It now lives in the top level toolz.py file. I also ignored the Python 2 compatibility code that was still in the conda version and instead updated based on the most recent toolz version.

It should also be noted that the get function being imported from conda._vendor.toolz was not being used and was not ported over.

See this issue for more information: conda/conda#11333

[travishathaway]

The test coverage in this repository is pretty low, so I would not rely on the tests passing as the best way to determine this is ready to be merged.

Does anyone know of another way we could test out the changes to make sure they haven't broken anything?

[larsoner]

Does anyone know of another way we could test out the changes to make sure they haven't broken anything?

I guess we could figure out the right commands manually every time to test any changes 😱 But this isn't sustainable, and it's also limited to one OS, etc...

The best way forward I think would be to improve the tests:

1. One way would be via additional pytest code that targets individual functions.

2. Another would be to adapt the code we use to build-install-test the installers on all three OSes in MNE-Python:

   https://github.com/mne-tools/mne-installers/blob/main/.github/workflows/build.yml

3. Really the best combination would probably be some pytest fixture magic that had build-and-install (to tmpdir) capabilities, i.e., something that took what we do in mne-installers and built it into a fixture somehow. For this the closest thing I can think of is the sphinx_app_wrapper from sphinx-gallery that makes it easy to do an isolated sphinx build via sphinx_app_wrapper.create_sphinx_app:

   https://github.com/sphinx-gallery/sphinx-gallery/blob/7347cd47a8623a89919fb3fd744150a074a49431/sphinx_gallery/tests/test_gen_gallery.py#L37-L41

   We'd have to see how long this took, but if it's only a few or tens of seconds per recipe, then we can try to make a diverse minimal set of recipes to hopefully hit most code paths...

[kenodegard]

As my comments suggest I'm clearly not a fan of copying code 😄

[kenodegard]

Oops! Sorry for not paying more attention and suggesting these changes during the last review. Most of these itertools use cases actually seem unnecessary and can be replaced with arg unpacking and list-comprehensions.

[jezdez]

Noice!

[kenodegard]

Just removing two unused imports

[beeankha]

👍