newVals[index] = Instance.missingValue();
vals[index] = Instance.missingValue();
  private void convertInstance(Instance instance) throws Exception {      int index = 0;    double [] newVals = new double [outputFormatPeek().numAttributes()];    for(int i = 0; i < getInputFormat().numAttributes(); i++) {      if (m_Keep[i]) {        if (instance.isMissing(i)) {          newVals[index] = Instance.missingValue();        } else {          newVals[index] = instance.value(i);        }        index++;      }    }    if (instance instanceof SparseInstance) {      push(new SparseInstance(instance.weight(), newVals));    } else {      push(new Instance(instance.weight(), newVals));    }  }