code: def _next_raw_dimension(self):
          
          dimension_dicts = self._dimension_dicts
          this_idx = dimension_dicts.index(self._dimension_dict)
          if this_idx > len(dimension_dicts) - 2:
              return None
          return _RawDimension(dimension_dicts[this_idx + 1], self._dimension_dicts)
docs: _RawDimension for next *dimension_dict* in sequence or None for last.
  
          Returns None if this dimension is the last in sequence for this cube.