What do these changes do?

Are there changes in behavior for the user?

I think the code is well written
Unit tests for the changes exist
Documentation reflects the changes
Add yourself to CONTRIBUTORS.txt
- The format is <Name> <Surname>.
- Please keep alphabetical order, the file is sorted by names.
Add a new entry to CHANGES.rst
- Choose any open position to avoid merge conflicts with other PRs.
- Add a link to the issue you are fixing (if any) using #issue_number format at the end of changelog message. Use Pull Request number if there are no issues for PR or PR covers the issue only partially.