code: def test_eight_schools_positional_argument(posterior):
      """`sample` does not allow positional arguments."""
      num_chains = 2
      with pytest.raises(
          TypeError, match=r"sample\(\) takes 1 positional argument"
      ):
          posterior.sample(num_chains)
  
file_path: pystan/tests/test_eight_schools.py
imports: import numpy
  import pandas
  import pytest
  import stan
label_desc: Use image node_id 6 for calling a global function with example usage: test_eight_schools_positional_argument(posterior) without return types