code: def test_single_chain(self, chains):
      # Test that no UserWarning is raised when sampling with NUTS defaults
  
      # When this test was added, a `UserWarning: More chains (500) than draws (1)` used to be issued
      # when sampling with a single chain
      warnings.simplefilter("error")
      with pm.Model():
          pm.Normal("x")
          pm.sample(chains=chains, return_inferencedata=True)
  
imports: import warnings
  from typing import Dict, Tuple
  import numpy
  import pytensor.tensor
  import pytest
  from arviz import InferenceData
  from arviz.tests.helpers import check_multiple_attrs
  from numpy import ma
  from pytensor.tensor.subtensor import AdvancedIncSubtensor, AdvancedIncSubtensor1
  import pymc
  from pymc.backends.arviz import InferenceDataConverter, predictions_to_inference_data, to_inference_data
  from pymc.exceptions import ImputationWarning
label_desc: Use image node_id 27 for calling the TestDataPyMC obj's underlying member method code with example usage: obj.test_single_chain(chains) without return types