merge method
Merges the cells starting from start
to end
.
If custom value
is not defined then it will look for the very first available value in range start
to end
by searching row-wise from left to right.
If sheet
does not exist then it will be automatically created.
Implementation
void merge(String sheet, CellIndex start, CellIndex end,
{dynamic customValue}) {
_availSheet(sheet);
_sheetMap[sheet]!.merge(start, end, customValue: customValue);
}