Improve code format and documentation

[rhumbertgz]

[antonvh]

Thanks for your very clear commit messages!

[antonvh]

Would you like to join our Slack channel? Email me on [email protected].

[antonvh]

I've been rather reluctant to add long docstrings because they seem to increase the size of compile micropython libraries and I want to be careful with memory.

[antonvh]

But maybe I worried for nothing: https://docs.micropython.org/en/latest/develop/compiler.html?highlight=main