Attribute temp = new Attribute(att.name(), newVals);
Instance newInstance = (Instance)instance.copy();
if (!newInstance.isMissing(m_AttIndex.getIndex())) {
String currValue = newInstance.stringValue(m_AttIndex.getIndex());
if(temp.indexOfValue(currValue) == -1)
newInstance.setValue(m_AttIndex.getIndex(), temp.indexOfValue(m_Label));
else
newInstance.setValue(m_AttIndex.getIndex(), temp.indexOfValue(currValue));
}