def short_label(self):
        """str: A short description of the group.

        >>> device.group.short_label
        'Kitchen + 1'
        """
        group_names = sorted([m.player_name for m in self.members])
        group_label = group_names[0]
        if len(group_names) > 1:
            group_label += " + {}".format(len(group_names) - 1)
        return group_label