@@ -, +, @@ 
    /**
     * Calls to getSeries().add(series) or to getSeries().remove(series) may corrupt
     * the workbook.
     * <p>
     * Instead, use the following methods:
     * <ul>
     * <li><code>int getSeriesCount()</code></li>
     * <li><code>void getSeries(int)</code></li>
     * <li><code>Series addSeries(XDDFDataSource,XDDFNumericalDataSource)</code></li>
     * <li><code>void removeSeries(int)</code></li>
     * </ul>
     *
     * @return
     */
    @Deprecated
    public List<Series> getSeries() {
        return series;
    }
    
    public final int getSeriesCount() {
        return series.size();
    }
    
    public final Series getSeries(int n) {
        return series.get(n);
    }
    
    public final void removeSeries(int n) {
        final String procName="removeSeries";
        if(n<0 || n>=series.size())
            throw new IllegalArgumentException(String.format(Locale.ROOT, "%s(%d): illegal index",procName,n));
        series.remove(n);
        _removeSeries(n);
    }
    
    /**
     * This method should be made abstract and implemented in every class that extends XDDFChartData.
     * <p>
     * A typical implementation would be
     * 
     * <pre><code>
    protected void _removeSeries(int n) {
        chart.removeSer(n);
    }
     * </code></pre>
     *
     * @param n
     */
    protected void _removeSeries(int n) {
        throw new RuntimeException("_removeSeries is not yet implemented for class "+getClass().getSimpleName());
    }