code: def _prepare_sort_by_score(self, values, sort_options):
          
          # create the keys
          base_tmp_key, tmp_keys = self._zset_to_keys(
                                      key=self._sort_by_sortedset['by'],
                                      values=values,
                                      )
          # ask to sort on our new keys
          sort_options['by'] = '%s:*' % base_tmp_key
  
          # retrieve original sort parameters
          for key in ('desc', 'alpha', 'get', 'store'):
              if key in self._sort_by_sortedset:
                  sort_options[key] = self._sort_by_sortedset[key]
  
          # if we want to get the score with values/values_list
          if sort_options.get('get'):
              try:
                  pos = sort_options['get'].index(SORTED_SCORE)
              except:
                  pass
              else:
                  sort_options['get'][pos] = '%s:*' % base_tmp_key
  
          return base_tmp_key, tmp_keys
docs: Create the key to sort on the sorted set references in
          self._sort_by_sortedset and adapte sort options