code: function() {
  
          var ancestors = [];
  
          if (!this.graph) {
              return ancestors;
          }
  
          var parentCell = this.getParentCell();
          while (parentCell) {
              ancestors.push(parentCell);
              parentCell = parentCell.getParentCell();
          }
  
          return ancestors;
      }
docs: Return an array of ancestor cells. The array is ordered from the parent of the cell to the most distant ancestor.