docs: def order_search(self, search):
          """Order given search by the ordering parameter given in request.
  
          :param search: ElasticSearch query object
  
          """
          ordering = self.get_query_param('ordering', self.ordering)
          if not ordering:
              return search
  
          sort_fields = []
          for raw_ordering in ordering.split(','):
              ordering_field = raw_ordering.lstrip('-')
              if ordering_field not in self.ordering_fields:
                  raise ParseError('Ordering by `{}` is not supported.'.format(ordering_field))
  
              ordering_field = self.ordering_map.get(ordering_field, ordering_field)
              direction = '-' if raw_ordering[0] == '-' else ''
              sort_fields.append('{}{}'.format(direction, ordering_field))
  
          return search.sort(*sort_fields)