code: def test_uninit_errors(backend):
      with backend() as be:
          with pytest.raises(AttributeError):
              be.get_last_sample()
  
          for k in ["chain", "log_prob", "blobs"]:
              with pytest.raises(AttributeError):
                  getattr(be, "get_" + k)()
  
file_path: emcee/src/emcee/tests/unit/test_backends.py
imports: import os
  from itertools import product
  from os.path import join
  import numpy
  import pytest
  from emcee import EnsembleSampler, State, backends
  from emcee.backends.hdf import does_hdf5_support_longdouble
label_desc: Use image node_id 6 for calling a global function with example usage: test_uninit_errors(backend) without return types