code: def testAssertions(self):
      base_operator_diag = tf.constant([1.0, 0.0])
      base_operator = tf.linalg.LinearOperatorDiag(
          base_operator_diag, is_positive_definite=True
      )
      cov_operator = tf.linalg.LinearOperatorLowRankUpdate(
          base_operator, u=tf.zeros((2, 2))
      )
      with self.assertRaises(Exception):
          dist = (
              MultivariateNormalLowRankUpdateLinearOperatorCovariance(
                  loc=None,
                  cov_operator=cov_operator,
                  validate_args=True,
              )
          )
          self.evaluate(dist.covariance())
  
imports: import collections
  from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import mvn_low_rank_update_linear_operator_covariance
  from tensorflow_probability.python.distributions import mvn_tril
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.stats import sample_stats
label_desc: Use image node_id 8 for calling the MultivariateNormalLowRankUpdateLinearOperatorCovarianceTest obj's underlying member method code with example usage: obj.testAssertions() without return types