@Override
    public Object getValueAt(final int row, final int column) {
      if(column == 0){
        return myPairs.get(row).getFirst();
      }
      else if(column == 1){
        return myPairs.get(row).getSecond();
      }
      else{
        throw new IllegalArgumentException("unknown column: " + column);
      }
    }
@Override
    public Object getValueAt(final int row, final int column)