docs: def _cells(self):
          """
          A sequence of |_Cell| objects, one for each cell of the layout grid.
          If the table contains a span, one or more |_Cell| object references
          are repeated.
          """
          col_count = self._column_count
          cells = []
          for tc in self._tbl.iter_tcs():
              for grid_span_idx in range(tc.grid_span):
                  if tc.vMerge == ST_Merge.CONTINUE:
                      cells.append(cells[-col_count])
                  elif grid_span_idx > 0:
                      cells.append(cells[-1])
                  else:
                      cells.append(_Cell(tc, self))
          return cells