code: def rownumber(self):
          
          if self._frame is not None and self._pos is not None:
              return self._frame.offset + self._pos
          return self._pos
docs: Read-only attribute providing the current 0-based index of the
          cursor in the result set or ``None`` if the index cannot be
          determined.
  
          The index can be seen as index of the cursor in a sequence
          (the result set). The next fetch operation will fetch the
          row indexed by :attr:`rownumber` in that sequence.