code: def test_fit_vector_draw_contents(fit):
      assert fit is not None
      offset = len(fit.sample_and_sampler_param_names)
      assert fit._draws.shape == (offset + 3, num_samples, num_chains)
      chain = fit._draws[:, :, 0]
      assert -1 < chain[offset + 0, :].mean() < 1
      assert 4 < chain[offset + 1, :].mean() < 6
      assert -1 < chain[offset + 2, :].mean() < 1
      beta = fit["beta"]
      assert beta.shape == (3, num_samples * num_chains)
      beta_mean = np.mean(beta, axis=1)
      assert -1 < beta_mean[0] < 1
      assert 4 < beta_mean[1] < 6
      assert -1 < beta_mean[2] < 1
  
imports: import numpy
  import pytest
  import stan
label_desc: Use image node_id 4 for calling a global function with example usage: test_fit_vector_draw_contents(fit) without return types