code: def testAddObsConvLayers(self):
      batch_size = 3
      num_obs_dims = 5
      num_actions_dims = 2
  
      obs_spec = tensor_spec.TensorSpec(
          [3, 3, num_obs_dims], tf.float32
      )
      action_spec = tensor_spec.TensorSpec(
          [num_actions_dims], tf.float32
      )
      critic_net = critic_network.CriticNetwork(
          (obs_spec, action_spec),
          observation_conv_layer_params=[(16, 3, 2)],
      )
  
      obs = tf.random.uniform([batch_size, 3, 3, num_obs_dims])
      actions = tf.random.uniform([batch_size, num_actions_dims])
      q_values, _ = critic_net((obs, actions))
      self.assertAllEqual(q_values.shape.as_list(), [batch_size])
      self.assertLen(critic_net.trainable_variables, 4)
  
file_path: agents/tf_agents/agents/ddpg/critic_network_test.py
imports: from absl.testing import parameterized
  import numpy
  import tensorflow
  from tf_agents.agents.ddpg import critic_network
  from tf_agents.specs import tensor_spec
label_desc: Use image node_id 2 for calling the CriticNetworkTest obj's underlying member method code with example usage: obj.testAddObsConvLayers() without return types