code: def test_NoNameserverCredentials(self):
      w = TestWorker(run_id="test")
  
      with tempfile.TemporaryDirectory() as working_directory:
          self.assertRaises(
              RuntimeError,
              w.load_nameserver_credentials,
              working_directory,
              num_tries=1,
          )
  
imports: import os
  import time
  import unittest
  import tempfile
  import logging
  import ConfigSpace
  from hpbandster.core.worker import Worker
  import hpbandster.core.nameserver
  from hpbandster.optimizers.hyperband import HyperBand
  from hpbandster.optimizers.bohb import BOHB
  from hpbandster.optimizers.h2bo import H2BO
  from hpbandster.optimizers.randomsearch import RandomSearch
label_desc: Use image node_id 5 for calling the TestWorkers obj's underlying member method code with example usage: obj.test_NoNameserverCredentials() without return types