code: def test_corr_matrix_sample():
      """Sample from a simple model."""
      posterior = stan.build(program_code, random_seed=1)
      fit = posterior.sample(num_chains=2, num_samples=50)
      df = fit.to_frame()
      assert len(df["Lambda.1.1"]) == 100
  
label_desc: Use image node_id 2 for calling a global function with example usage: test_corr_matrix_sample() without return types