/*
  public static Instances useFilter(Instances data,				    Filter filter) throws Exception {    System.err.println(filter.getClass().getName()                        + " in:" + data.numInstances());    for (int i = 0; i < data.numInstances(); i++) {      filter.input(data.instance(i));    }    filter.batchFinished();    Instances newData = filter.outputFormat();    Instance processed;    while ((processed = filter.output()) != null) {      newData.add(processed);    }    System.err.println(filter.getClass().getName()                        + " out:" + newData.numInstances());    return newData;  }