code: def test_log_prob(posterior, x: float, y: float):
      constrained_params = posterior.constrain_pars([x, y])
      assert np.allclose(x, constrained_params[0])
      assert np.allclose(np.exp(y), constrained_params[1])
      assert np.allclose(x * 2, constrained_params[2])
      assert np.allclose(x + np.exp(y), constrained_params[3])
  
imports: import random
  import numpy
  import pytest
  import stan
label_desc: Use image node_id 2 for calling a global function with example usage: test_log_prob(posterior, x, y) without return types