public List<CommittedChangeList> writeChanges(final List<? extends CommittedChangeList> changes) throws IOException {
    // the list and index are sorted in direct chronological order
    changes.sort(CommittedChangeListByDateComparator.ASCENDING);
    return writeChanges(changes, null);
  }
public List<CommittedChangeList> writeChanges(final List<? extends CommittedChangeList> changes)