code: def sort_index(self, axis=0, level=None, ascending=True, inplace=False,
                     kind='quicksort', na_position='last',
                     sort_remaining=True, by=None):
          
          return self._frame.sort_index(axis=axis, level=level,
                                        ascending=ascending, inplace=inplace,
                                        kind=kind, na_position=na_position,
                                        sort_remaining=sort_remaining, by=by)
docs: Sort object by labels (along an axis)
  
          Wrapper around the :meth:`pandas.DataFrame.sort_index` method.