          elif content_type is None:
              content_type = media_type
          self['Content-Type'] = content_type
  
          ret = renderer.render(self.data, media_type, context)
          if isinstance(ret, six.text_type):
              assert charset, (
                  'renderer returned unicode, and did not specify '
                  'a charset value.'
              )
 
</s> remove         self.renderers = [MockJSONRenderer(), MockHTMLRenderer()]
 </s> add         self.renderers = [MockJSONRenderer(), MockHTMLRenderer(), MockOpenAPIRenderer()]
        ret = renderer.render(self.data, accepted_media_type, context)
          elif content_type is None:
              content_type = media_type
          self['Content-Type'] = content_type
  
        ret = renderer.render(self.data, accepted_media_type, context)
          if isinstance(ret, six.text_type):
              assert charset, (
                  'renderer returned unicode, and did not specify '
                  'a charset value.'
              )
keep keep keep keep replace keep keep keep keep keep
 Fix json indent parameter. Closes #4281 (#4313) 
rest_framework/response.py