docs: function(){
          if (this._slicer) {
            this._slicer.close();
          }
          var i, n = this._numAxes;
          for (i = 0; i < n; i++) {
            this.getAxis(i).close();
          }
          this._cellset.close();
          this._cellset = null;
          this._root = null;
          this._axes = null;
          this._axesOrder = null;
          this._numAxes = null;
          this._slicer = null;
      }