There is a new pip-tools release. A commit [removing the test dependency
on six] is included in this release, so several tests that now pass are
being re-enabled in the check phase. The six-specific tests that still
don't pass require network access and remain disabled. Finally, drop the
dependency on first, which has been dropped by pip-tools. The full
changelog is available at f28d1a7d25/CHANGELOG.md (430-2019-11-25).
[removing the test dependency on six]: https://github.com/jazzband/pip-tools/pull/939
f9ef45b183