Standardize formatting

[seanpmorgan]

Would like to standardize repository style using a code formatter. @facaiy suggested https://github.com/google/yapf which looks like it would work very nicely.

In the future this should be tied in with our CI testing

[facaiy]

yapf cannot handle document correctly, I have once used docformatter tool:

• https://pypi.org/project/docformatter/
  currently automatically formats docstrings to follow a subset of the PEP 257 conventions.

[lgeiger]

One other very popular code formatter to consider would be https://github.com/ambv/black

[seanpmorgan]

Thanks, I've used black extensively on other projects and love it. I didn't mention it because I didn't want to argue for its departures from PEP8, but it's certainly an option.

[facaiy]

@karmel Hi, Karmel. Do you have any suggestion? I think sanity checker is really useful to reduce the burdens of reviewer.

[karmel]

There are two pieces here-- autoformatting, and linting when we run tests to block merges with lint errors.

I think you should pick the tool you all prefer, though it's complicated by the fact that TF adheres to the Google Python style guide, which deviates slightly from PEP8 (ie, two-space tabs). Ideally, then, a formatter that is configurable would be best.

For TF Models, we didn't set up an autoformatter, but we did set up a pylint check with a custom rcfile that approximated Google's style guidelines. We can copy that here if you want, or use whatever you think best.

[facaiy]

@karmel Thank your for the input. I think it's better to stick with PEP8, which is supported by nearly all python toolchains (IDE, text editor, etc).

Yes, both yapf and pylint are configurable. I'll submit a shell script later for the issue.