Failing with #6, we're proceeding with python3.7 -m venv .... Looking at setup.py there're bunch of dvr-* entrypoint. But running them have no effect:

(.venv) dvrip$ dvr-info
Usage:  info
(.venv) dvrip$ dvr-info 192.168.1.10
Usage:  info
(.venv) dvrip$ dvr-info -h 192.168.1.10
Usage:  info

That's apparently because "calling conventions" for subcommands have changed, and nowadays

	if host() is None:
		usage()

is always true.