code: def test_parameters_lookup(self):
      @auto_composite_tensor.auto_composite_tensor
      class ThingWithParametersButNoAttrs(
          auto_composite_tensor.AutoCompositeTensor
      ):
          def __init__(self, a, b):
              self.a = tf.convert_to_tensor(
                  a, dtype_hint=tf.float32, name="a"
              )
              self.b = tf.convert_to_tensor(
                  b, dtype_hint=tf.float32, name="a"
              )
              self.parameters = dict(a=self.a, b=self.b)
  
      t = ThingWithParametersButNoAttrs(1.0, 2.0)
      self.assertIsInstance(t, tf.__internal__.CompositeTensor)
  
      ts = t._type_spec
      components = ts._to_components(t)
      self.assertAllEqualNested(components, dict(a=1.0, b=2.0))
  
      t2 = ts._from_components(components)
      self.assertIsInstance(t2, ThingWithParametersButNoAttrs)
  
imports: import functools
  import os
  from absl import flags
  from absl.testing import parameterized
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import bijector
  from tensorflow_probability.python.bijectors import reshape
  from tensorflow_probability.python.bijectors import scale
  from tensorflow_probability.python.bijectors import shift
  from tensorflow_probability.python.bijectors import transform_diagonal
  from tensorflow_probability.python.distributions import independent
  from tensorflow_probability.python.distributions import normal
  from tensorflow_probability.python.distributions import transformed_distribution
  from tensorflow_probability.python.experimental.distributions import mvn_precision_factor_linop
  from tensorflow_probability.python.internal import auto_composite_tensor
  from tensorflow_probability.python.internal import tensor_util
  from tensorflow_probability.python.internal import test_util
  from absl.testing import absltest
label_desc: Use image node_id 9 for calling the AutoCompositeTensorTest obj's underlying member method code with example usage: obj.test_parameters_lookup() without return types