code: def _copy_from_previous(self, cell):
          
          previous = self._previous_cell
          if previous is not None:
              if not cell.row_key:
                  cell.row_key = previous.row_key
                  if not cell.family_name:
                      cell.family_name = previous.family_name
                      # NOTE: ``cell.qualifier`` **can** be empty string.
                      if cell.qualifier is None:
                          cell.qualifier = previous.qualifier
docs: Helper for :meth:`consume_next`.