          template = loader.get_template(self.template)
          return template_render(template, context)
  
  
  class OrderingFilter(BaseFilterBackend):
      # The URL query parameter used for the ordering.
      ordering_param = api_settings.ORDERING_PARAM
      ordering_fields = None
      template = 'rest_framework/filters/ordering.html'
 
</s> remove         urls = []
 </s> add         urls = super(DefaultRouter, self).get_urls()
    def get_fields(self, view):
        return [self.search_param]

          template = loader.get_template(self.template)
          return template_render(template, context)
  
    def get_fields(self, view):
        return [self.search_param]

  
  class OrderingFilter(BaseFilterBackend):
      # The URL query parameter used for the ordering.
      ordering_param = api_settings.ORDERING_PARAM
      ordering_fields = None
      template = 'rest_framework/filters/ordering.html'
keep keep add keep keep 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