def _kl_blockwise_blockwise(b0, b1, name=None):
  """
  """
  if len(b0.distributions) != len(b1.distributions):
    raise ValueError(
        'Can only compute KL divergence between Blockwise distributions with '
        'the same number of component distributions.')

  # We also need to check that the event shapes match for each one.
  b0_event_sizes = [_event_size(d) for d in b0.distributions]
  b1_event_sizes = [_event_size(d) for d in b1.distributions]

  assertions = []
  message = ('Can only compute KL divergence between Blockwise distributions '
             'with the same pairwise event shapes.')

  if (all(isinstance(event_size, int) for event_size in b0_event_sizes) and
      all(isinstance(event_size, int) for event_size in b1_event_sizes)):
    if b0_event_sizes != b1_event_sizes:
      raise ValueError(message)
  else:
    if b0.validate_args or b1.validate_args:
      assertions.extend(
          assert_util.assert_equal(  # pylint: disable=g-complex-comprehension
              e1, e2, message=message)
          for e1, e2 in zip(b0_event_sizes, b1_event_sizes))

  with tf.name_scope(name or 'kl_blockwise_blockwise'):
    with tf.control_dependencies(assertions):
      return sum([
          kullback_leibler.kl_divergence(d1, d2) for d1, d2 in zip(
              b0.distributions, b1.distributions)])