code: def json(self, answer):
          
  
          self.content_type = "application/json"
          if hasattr(answer, '__json__'):
              answer = answer.__json__()
          elif isinstance(answer, list):
              newanswer = []
              for elem in answer:
                  if hasattr(elem, '__json__'):
                      elem = elem.__json__()
                  newanswer.append(elem)
              answer = newanswer
          if self._output_schema is not None:
              try:
                  jsonschema.validate(answer, self._output_schema)
              except jsonschema.ValidationError as e:
                  log.error("Invalid output query. JSON schema error: {}".format(e.message))
                  raise aiohttp.web.HTTPBadRequest(text="{}".format(e))
          self.body = json.dumps(answer, indent=4, sort_keys=True).encode('utf-8')
docs: Set the response content type to application/json and serialize
          the content.
  
          :param anwser The response as a Python object