UsageRecordList usageRecords = client.getAccount().getUsageRecords();
TreeSet<UsageRecord> answers = new TreeSet<UsageRecord>(new Comparator<UsageRecord>() {
@Override
public int compare(UsageRecord o1, UsageRecord o2) {
UsageCategory o1_category = o1.getCategory();
UsageCategory o2_category = o2.getCategory();
if (o1_category == null) {
return 1;
} else if (o2_category == null) {
return -1;
} else {