code: def docker_machine_id():  # type: () -> Tuple[Optional[int], Optional[int]]
      
      machine_name = docker_machine_name()
      if not machine_name:
          return (None, None)
      uid = cmd_output_to_int(['docker-machine', 'ssh', machine_name, "id -u"])
      gid = cmd_output_to_int(['docker-machine', 'ssh', machine_name, "id -g"])
      return (uid, gid)
docs: Asks docker-machine for active machine and gets the UID of the docker user
      inside the vm
      :return: tuple (UID, GID), or (None, None) if error (e.g. docker-machine not present or stopped)