docs: function SunburstPiece(node, seriesModel, ecModel) {
  
      graphic.Group.call(this);
  
      var sector = new graphic.Sector({
          z2: DEFAULT_SECTOR_Z
      });
      sector.seriesIndex = seriesModel.seriesIndex;
  
      var text = new graphic.Text({
          z2: DEFAULT_TEXT_Z,
          silent: node.getModel('label').get('silent')
      });
      this.add(sector);
      this.add(text);
  
      this.updateData(true, node, 'normal', seriesModel, ecModel);
  
      // Hover to change label and labelLine
      function onEmphasis() {
          text.ignore = text.hoverIgnore;
      }
      function onNormal() {
          text.ignore = text.normalIgnore;
      }
      this.on('emphasis', onEmphasis)
          .on('normal', onNormal)
          .on('mouseover', onEmphasis)
          .on('mouseout', onNormal);
  }