Automatic merge from submit-queue (batch tested with PRs 41349, 41532, 41256, 41587, 41657)

Lint fixes for the master and worker Python code.

**What this PR does / why we need it**: lint fixes for the python code.

**Which issue this PR fixes** none

**Special notes for your reviewer**: This is lint fixes for the Juju python code.

**Release note**:

```release-note
NONE
```

Please consider these changes so we can pass flake8 lint tests in our build process.