code: function PiePiece(data, idx) {
  
      graphic.Group.call(this);
  
      var sector = new graphic.Sector({
          z2: 2
      });
      var polyline = new graphic.Polyline();
      var text = new graphic.Text();
      this.add(sector);
      this.add(polyline);
      this.add(text);
  
      this.updateData(data, idx, true);
  }
docs: Piece of pie including Sector, Label, LabelLine
  @constructor
  @extends {module:zrender/graphic/Group}