          raise NotImplementedError(".filter_queryset() must be overridden.")
  
  
  class DjangoFilterBackend(BaseFilterBackend):
      """
      A filter backend that uses django-filter.
 
</s>
    def get_fields(self, view):
        return []

          raise NotImplementedError(".filter_queryset() must be overridden.")
  
    def get_fields(self, view):
        return []

  
  class DjangoFilterBackend(BaseFilterBackend):
      """
      A filter backend that uses django-filter.
keep add keep keep keep keep
 Schemas & client libraries. (#4179)

* Added schema generation support.
* New tutorial section.
* API guide on schema generation.
* Topic guide on API clients.
rest_framework/filters.py