code: def testVonMisesSampleMoments(self):
      locs_v = np.array([-1.0, 0.3, 2.3])
      concentrations_v = np.array([1.0, 2.0, 10.0])
      dist = von_mises.VonMises(
          self.make_tensor(locs_v),
          self.make_tensor(concentrations_v),
          validate_args=True,
      )
  
      n = 10000
      seed = test_util.test_seed()
      samples = dist.sample(n, seed=seed)
  
      expected_mean = dist.mean()
      actual_mean = tf.atan2(
          tf.reduce_mean(tf.sin(samples), axis=0),
          tf.reduce_mean(tf.cos(samples), axis=0),
      )
  
      expected_variance = dist.variance()
      standardized_samples = samples - tf.expand_dims(dist.mean(), 0)
      variance_samples = 1.0 - tf.cos(standardized_samples)
  
      [
          expected_mean_val,
          expected_variance_val,
          actual_mean_val,
          variance_samples_,
      ] = self.evaluate(
          [
              expected_mean,
              expected_variance,
              actual_mean,
              variance_samples,
          ]
      )
  
      # TODO(axch, cgs): atan2(means) is not mean(atan2), but maybe there
      # is a formulation of what this is testing that does use IID samples
      # and is amenable to assertAllMeansClose?
      self.assertAllClose(actual_mean_val, expected_mean_val, rtol=0.1)
      self.assertAllMeansClose(
          variance_samples_, expected_variance_val, axis=0, rtol=0.1
      )
  
imports: import numpy
  from scipy import special
  from scipy import stats
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.distributions import von_mises
  from tensorflow_probability.python.internal import dtype_util
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 19 for calling the _VonMisesTest obj's underlying member method code with example usage: obj.testVonMisesSampleMoments() without return types