      default_schema_renderers = [renderers.CoreJSONRenderer]
  
      def __init__(self, *args, **kwargs):
          self.schema_title = kwargs.pop('schema_title', None)
          self.schema_renderers = kwargs.pop('schema_renderers', self.default_schema_renderers)
          super(DefaultRouter, self).__init__(*args, **kwargs)
  
 
</s> remove         self.renderers = [MockJSONRenderer(), MockHTMLRenderer()]
 </s> add         self.renderers = [MockJSONRenderer(), MockHTMLRenderer(), MockOpenAPIRenderer()] </s> remove         ret = renderer.render(self.data, media_type, context)
 </s> add         ret = renderer.render(self.data, accepted_media_type, context)
        if 'schema_renderers' in kwargs:
            assert 'schema_title' in kwargs, 'Missing "schema_title" argument.'
      default_schema_renderers = [renderers.CoreJSONRenderer]
  
      def __init__(self, *args, **kwargs):
        if 'schema_renderers' in kwargs:
            assert 'schema_title' in kwargs, 'Missing "schema_title" argument.'
          self.schema_title = kwargs.pop('schema_title', None)
          self.schema_renderers = kwargs.pop('schema_renderers', self.default_schema_renderers)
          super(DefaultRouter, self).__init__(*args, **kwargs)
  
keep keep add keep keep keep keep
 Fix json indent parameter. Closes #4281 (#4313) 
rest_framework/routers.py