True if one or more cells in range are part of a merged cell.

def contains_merged_cell(self):
        """True if one or more cells in range are part of a merged cell."""
        for tc in self.iter_tcs():
            if tc.gridSpan > 1:
                return True
            if tc.rowSpan > 1:
                return True
            if tc.hMerge:
                return True
            if tc.vMerge:
                return True
        return False