Merging cells in Excel using Apache POI

Is there any other way to merge cells in Excel using Apache POI library?

I was trying using the following, but its not working

// selecting the region in Worksheet for merging data
CellRangeAddress region = CellRangeAddress.valueOf("A" + rowNo + ":D"
            + rowNo);

// merging the region
sheet1.addMergedRegion(region);

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