code: def sort_values(self, return_indexer=False, ascending=True):
          
          if return_indexer:
              _as = self.argsort()
              if not ascending:
                  _as = _as[::-1]
              sorted_index = self.take(_as)
              return sorted_index, _as
          else:
              sorted_values = np.sort(self._ndarray_values)
              attribs = self._get_attributes_dict()
              freq = attribs['freq']
  
              if freq is not None and not is_period_dtype(self):
                  if freq.n > 0 and not ascending:
                      freq = freq * -1
                  elif freq.n < 0 and ascending:
                      freq = freq * -1
              attribs['freq'] = freq
  
              if not ascending:
                  sorted_values = sorted_values[::-1]
  
              return self._simple_new(sorted_values, **attribs)
docs: Return sorted copy of Index.