code: def test_maybe_expand_trailing_dim(self):
      for shape_in, expected_shape_out in [
          # pyformat: disable
          ([4, 3], [4, 3, 1]),
          ([4, 3, 1], [4, 3, 1]),
          ([4], [4, 1]),
          ([1], [1]),
          ([4, 1], [4, 1])
          # pyformat: enable
      ]:
          shape_out = self._shape_as_list(
              sts_util._maybe_expand_trailing_dim(
                  self._build_tensor(np.zeros(shape_in))
              )
          )
          self.assertAllEqual(shape_out, expected_shape_out)
  
imports: from absl.testing import parameterized
  import numpy
  import pandas
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import mvn_diag
  from tensorflow_probability.python.distributions import mvn_tril
  from tensorflow_probability.python.distributions import normal
  from tensorflow_probability.python.internal import tensorshape_util
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.sts.components import local_level
  from tensorflow_probability.python.sts.internal import missing_values_util
  from tensorflow_probability.python.sts.internal import util
label_desc: Use image node_id 2 for calling the _UtilityTests obj's underlying member method code with example usage: obj.test_maybe_expand_trailing_dim() without return types