code: List<MemberState> getPassiveMemberStates(Comparator<MemberState> comparator) {
      List<MemberState> passiveMembers = new ArrayList<>(getPassiveMemberStates());
      Collections.sort(passiveMembers, comparator);
      return passiveMembers;
    }
docs: Returns a list of passive members.
  
  @param comparator A comparator with which to sort the members list.
  @return The sorted members list.