code: def test_fit_scalar_param(fit):
      y = fit["y"]
      assert y.shape == (1, num_samples * num_chains)
      assert 9 < np.mean(y) < 11
  
file_path: pystan/tests/test_fit_basic_scalar.py
imports: import numpy
  import pytest
  import stan
label_desc: Use image node_id 4 for calling a global function with example usage: test_fit_scalar_param(fit) without return types