Change asserts to exceptions

[caternuson]

Not urgent. Just noticed this lib is still using asserts.
https://circuitpython.readthedocs.io/en/latest/docs/design_guide.html#exceptions-and-asserts

[jposada202020]

@caternuson just for my info, what is the goal here, use exceptions instead of assert n the library?. thanks :)

[caternuson]

Yep. See linked design guide info. Other CP libs could also be good reference. In general, this is a trivial change. I'll add a good first issue tag also FWIW.

[jposada202020]

will do, thanks :)

[jposada202020]

solved by #21

[caternuson]

Thanks!