code: def testDocstring1(self):
      d = blockwise.Blockwise(
          [
              independent.Independent(
                  normal.Normal(
                      loc=tf1.placeholder_with_default(
                          tf.zeros(4, dtype=tf.float64),
                          shape=None,
                      ),
                      scale=1,
                  ),
                  reinterpreted_batch_ndims=1,
              ),
              mvn_tril.MultivariateNormalTriL(
                  scale_tril=tf1.placeholder_with_default(
                      tf.eye(2, dtype=tf.float32), shape=None
                  )
              ),
          ],
          dtype_override=tf.float32,
          validate_args=True,
      )
      x = d.sample([2, 1], seed=test_util.test_seed())
      y = d.log_prob(x)
      x_, y_ = self.evaluate([x, y])
      self.assertEqual((2, 1, 4 + 2), x_.shape)
      self.assertDTypeEqual(x, np.float32)
      self.assertEqual((2, 1), y_.shape)
      self.assertDTypeEqual(y, np.float32)
  
      self.assertAllClose(
          np.zeros((6,), dtype=np.float32), self.evaluate(d.mean())
      )
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import blockwise
  from tensorflow_probability.python.distributions import exponential
  from tensorflow_probability.python.distributions import gamma
  from tensorflow_probability.python.distributions import independent
  from tensorflow_probability.python.distributions import joint_distribution_coroutine
  from tensorflow_probability.python.distributions import joint_distribution_named
  from tensorflow_probability.python.distributions import joint_distribution_sequential
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.distributions import mvn_linear_operator
  from tensorflow_probability.python.distributions import mvn_tril
  from tensorflow_probability.python.distributions import normal
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 1 for calling the BlockwiseTest obj's underlying member method code with example usage: obj.testDocstring1() without return types