code: def _check_request_results(self, results):
          
          responses = []
          failed_endpoints = []
          for index, result_tuple in enumerate(results):
              success, result = result_tuple
              if success:
                  responses.append(result)
              else:
                  endpoint = self.endpoints[index]
                  self.log.failure(
                      'Failed to make a request to a marathon-lb instance: '
                      '{endpoint}', result, LogLevel.error, endpoint=endpoint)
                  responses.append(None)
                  failed_endpoints.append(endpoint)
  
          if len(failed_endpoints) == len(self.endpoints):
              raise RuntimeError(
                  'Failed to make a request to all marathon-lb instances')
  
          if failed_endpoints:
              self.log.error(
                  'Failed to make a request to {x}/{y} marathon-lb instances: '
                  '{endpoints}', x=len(failed_endpoints), y=len(self.endpoints),
                  endpoints=failed_endpoints)
  
          return responses
docs: Check the result of each request that we made. If a failure occurred,
          but some requests succeeded, log and count the failures. If all
          requests failed, raise an error.
  
          :return:
              The list of responses, with a None value for any requests that
              failed.