code: function (start, end) {
        var fnCellValue = instance.custom.cellValue,
            coordsStart = instance.utils.cellCoords(start),
            coordsEnd = instance.utils.cellCoords(end),
            element = this;
  
        // iterate cells to get values and indexes
        var cells = instance.utils.iterateCells.call(this, coordsStart, coordsEnd),
            result = [];
  
        // check if custom cellValue fn exists
        if (instance.utils.isFunction(fnCellValue)) {
  
          var cellId = instance.utils.translateCellCoords({row: element.row, col: element.col});
  
          //update dependencies
          instance.matrix.updateItem(cellId, {deps: cells.index});
  
        } else {
  
          //update dependencies
          instance.matrix.updateElementItem(element, {deps: cells.index});
        }
  
        result.push(cells.value);
        return result;
      }
docs: Get cell range values
  @param {String} start cell A1
  @param {String} end cell B3
  @returns {Array}