r"""
        Check following rows, whether row should be a multirow

        e.g.:     becomes:
        a & 0 &   \multirow{2}{*}{a} & 0 &
          & 1 &     & 1 &
        b & 0 &   \cline{1-2}
                  b & 0 &

def _format_multirow(self, row, ilevels, i, rows):
        r"""
        Check following rows, whether row should be a multirow

        e.g.:     becomes:
        a & 0 &   \multirow{2}{*}{a} & 0 &
          & 1 &     & 1 &
        b & 0 &   \cline{1-2}
                  b & 0 &
        """
        for j in range(ilevels):
            if row[j].strip():
                nrow = 1
                for r in rows[i + 1:]:
                    if not r[j].strip():
                        nrow += 1
                    else:
                        break
                if nrow > 1:
                    # overwrite non-multirow entry
                    row[j] = '\\multirow{{{nrow:d}}}{{*}}{{{row:s}}}'.format(
                        nrow=nrow, row=row[j].strip())
                    # save when to end the current block with \cline
                    self.clinebuf.append([i + nrow - 1, j + 1])
        return row