Thanks for the PR!

I did a bit of nitpicking. Please add the is_* thingies to Chat, too. Also, we'll need some unittests. Have a look at tests/test_{user/chat}.py some inspiration :) if you want to run one one single test for checking, if it works, you can use pytest -k test_function_name.

Finally, I feel like it would be cleaner to make the is_* thingies properties instead of attributes. While no one in the right mind would change the chats id after initialization, properties could still catch that and also that way it would be clearer that it's just a convenience thingy. So IMHO it should be something like this.

Thanks, that looks good :) I left some minor reformulation suggestions. But I'd like @Poolitzer to review anyway, so he can decide about those.

left two minor comments, thanks for the improvement!