unMerge method
unMerge the merged cells.
var sheet = 'DesiredSheet';
List<String> spannedCells = excel.getMergedCells(sheet);
var cellToUnMerge = "A1:A2";
excel.unMerge(sheet, cellToUnMerge);
Implementation
void unMerge(String sheet, String unmergeCells) {
if (_sheetMap[sheet] != null) {
_sheetMap[sheet]!.unMerge(unmergeCells);
}
}