text: public SheetRefEvaluator getSheetEvaluator(int sheetIndex) {if (sheetIndex < _firstSheetIndex || sheetIndex > _lastSheetIndex) {throw new IllegalArgumentException("Invalid SheetIndex: " + sheetIndex +" - Outside range " + _firstSheetIndex + " : " + _lastSheetIndex);}return _sheetEvaluators[sheetIndex-_firstSheetIndex];}