code: def test_log_prob_normalized(concentration):
      grid = torch.arange(0.0, 2 * math.pi, 1e-4)
      prob = VonMises(0.0, concentration).log_prob(grid).exp()
      norm = prob.mean().item() * 2 * math.pi
      assert abs(norm - 1) < 1e-3, norm
  
file_path: pyro/tests/distributions/test_von_mises.py
imports: import math
  import os
  import pytest
  import torch
  from torch import optim
  from pyro.distributions import VonMises, VonMises3D
  from pyro.distributions.testing.gof import auto_goodness_of_fit
  from tests.common import TEST_FAILURE_RATE, skipif_param, xfail_if_not_implemented
label_desc: Use image node_id 5 for calling a global function with example usage: test_log_prob_normalized(concentration) without return types