<chart palette="2" caption="Unit Sales" xAxisName="Month" yAxisName="Units" showValues="0" decimals="0" formatNumberScale="0" useRoundEdges="1">
<set label="Jan" value="462" />
<set label="Feb" value="857" />
<set label="Mar" value="671" />
<set label="Apr" value="494" />
<set label="May" value="761" />
<set label="Jun" value="960" />
</chart>
怎么解析节点set的属性label和value?