code: public void setRowsSpanned(final int rowIndex, final int n) throws IOException {
          if (n <= 1) return;
  
          final TableCell firstCell = this.getOrCreateCell(rowIndex);
          if (firstCell.isCovered()) return;
  
          this.parent.setRowsSpanned(this.rowIndex, rowIndex, n);
      }
docs: Add a span across rows
  
  @param rowIndex the index of the first row
  @param n        the number of rows in the span
  @throws IOException if the cells can't be merged