## Description

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<!-- If this is a new feature, reference what paper it implements. -->


## Checklist

<!-- It's fine to submit PRs which are a work in progress! -->
<!-- But before they are merged, all PRs should provide: -->
- [Docstrings for all functions](https://github.com/numpy/numpy/blob/master/doc/example.py)
- Gallery example in `./doc/examples` (new features only)
- Benchmark in `./benchmarks`, if your changes aren't covered by an
  existing benchmark
- Unit tests
- Clean style in [the spirit of PEP8](https://www.python.org/dev/peps/pep-0008/)
- Descriptive commit messages (see below)

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## For reviewers

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- Check that the PR title is short, concise, and will make sense 1 year
  later.
- Check that new functions are imported in corresponding `__init__.py`.
- Check that new features, API changes, and deprecations are mentioned in
      `doc/release/release_dev.rst`.
