docs: def _transform_row(self, in_row, out_row):
          """
          Transforms an input row to an output row (i.e. (partial) dimensional data).
  
          :param dict[str,str] in_row: The input row.
          :param dict[str,T] out_row: The output row.
  
          :rtype: (str,str)
          """
          tmp_row = {}
  
          for step in self._steps:
              park_info, ignore_info = step(in_row, tmp_row, out_row)
              if park_info or ignore_info:
                  return park_info, ignore_info
  
          return None, None