Shouldn't BusState be an enum?

[felixdivo]

Currently, BusState is defined as

BusState = namedtuple('BusState', 'ACTIVE, PASSIVE, ERROR')

But shouldn't it be an enum?

[felixdivo]

We could use https://pypi.org/project/enum34/ to make it work with Python < 3.4 as well.

[hardbyte]

Yeah let's do it, I'd like to use Enum types in a few places if we added the dependency.