code standards enforced by pre-commit hooks

## an explicit code standard, enforced by `pre-commits`

As a [developer], I want [explicit & automagic enforcing of code standards] so that [code is homogeneous, commits are compacts and maintainers are relieved from nitpicking].

## Details

Code standards are important, but a fatiguing to embrace [if not automated](https://www.linkedin.com/pulse/improving-your-python-development-workflow-guide-black-githumbi/).

**Describe the solution you'd like**
[Pre-commits seems a nice way to go about this](https://gist.github.com/guptarohit/35f49bc663620d03ca00d2a0ff7429df).

More tooling might scare off new devs, conversely tooling allows maintainers to whip PR's in shape and merge with confidence.