Add example for TLS.
<!--
If you know who should review your pull request, please assign it to
that
person, otherwise the pull request would get assigned randomly.
If your pull request is for a specific language, please add the
appropriate
lang label.
-->
- Switched from yapf to black
- Reconfigure isort for black
- Resolve black/pylint idiosyncrasies
Note: I used `--experimental-string-processing` because black was
producing "implicit string concatenation", similar to what described
here: https://github.com/psf/black/issues/1837. While currently this
feature is experimental, it will be enabled by default:
https://github.com/psf/black/issues/2188. After running black with the
new string processing so that the generated code merges these `"hello" "
world"` strings concatenations, then I removed
`--experimental-string-processing` for stability, and regenerated the
code again.
To the reviewer: don't even try to open "Files Changed" tab 😄 It's
better to review commit-by-commit, and ignore `run black and isort`.
* Add isort_code.sh to sanity tests
* Run tools/distrib/isort_code.sh
* Fine tune the import order for relative imports
* Make pylint and project generation happy
* Fix a few corner cases
* Use --check instead of --diff
* The import order impacts test result somehow
* Make isort print diff and check output at the same time
* Let tools/run_tests/python_utils be firstparty library
* Run isort against latest HEAD
* Add type annotations
* Add test for asyncio auth example
* Use dynamic stubs to allow same code runs manually and under Bazel
* Add grpcio-tools as a Bazel dependency
* asyncio.run is not yet existed in 3.6
* Improve readability