12-10-2018 13:31 PST

- Import `iam.policy` from `google.api_core`. ([#6741](https://github.com/googleapis/google-cloud-python/pull/6741))

- Accomodate new back-end restriction on retention period. ([#6388](https://github.com/googleapis/google-cloud-python/pull/6388))

- Avoid deleting a blob renamed to itself ([#6365](https://github.com/googleapis/google-cloud-python/pull/6365))

- Update dependency to google-cloud-core ([#6835](https://github.com/googleapis/google-cloud-python/pull/6835))

- Bump minimum `api_core` version for all GAPIC libs to 1.4.1. ([#6391](https://github.com/googleapis/google-cloud-python/pull/6391))

- Normalize use of support level badges ([#6159](https://github.com/googleapis/google-cloud-python/pull/6159))

- Blacken libraries ([#6794](https://github.com/googleapis/google-cloud-python/pull/6794))

- Add templates for flake8, coveragerc, noxfile, and black. ([#6642](https://github.com/googleapis/google-cloud-python/pull/6642))

- Harden teardown in system tests. ([#6444](https://github.com/googleapis/google-cloud-python/pull/6444))

- Harden `create_bucket` call in systests vs. 429 TooManyRequests. ([#6401](https://github.com/googleapis/google-cloud-python/pull/6401))

- Skip public bucket test in VPC Service Controls ([#6230](https://github.com/googleapis/google-cloud-python/pull/6230))

- Fix lint failure. ([#6219](https://github.com/googleapis/google-cloud-python/pull/6219))

- Disable test running in VPC Service Controls restricted environment ([#6215](https://github.com/googleapis/google-cloud-python/pull/6215))

- Use new Nox ([#6175](https://github.com/googleapis/google-cloud-python/pull/6175))