hello, the python SDK support for state channels is experimental, it doesn’t contains tests and the support is limited, that is why is not mentioned on the documentation.
The main effort has been dedicated to make the current functionalities more accessible (see contract interface) and documented to address the feedback received.
There are now two major topics to address for the python SDK development to address, one is support for state channels and the other is support for the aeternal middleware.
I planned to make a forum post asking which of the two prioritize in the beginning of the 2020, do you think it would be useful? Until now the feedback that I have collected directly and indirectly was always about keep the SDK as stable as possible (especially during forks), contracts support and documentation. The major effort lately was on documenting.
For the JS SDK there are quite a few examples how to use the state channels, the latest one was made in december, it still hast to be polished but here is the link anyway: pay-per-frame
Another one would be the gomoku game, that also should be fine, but please open an issue if you find problems.