code: def testTrainableVariables(self):
      bias = bias_layer.BiasLayer(
          bias_initializer=tf.constant_initializer(value=1.0)
      )
      states = tf.zeros((2, 3))
      _ = bias(states)
      self.evaluate(tf.compat.v1.global_variables_initializer())
      variables = bias.trainable_variables
      np.testing.assert_almost_equal(
          [[1.0] * 3], self.evaluate(variables)
      )
  
file_path: agents/tf_agents/keras_layers/bias_layer_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import tensorflow
  from tf_agents.keras_layers import bias_layer
label_desc: Use image node_id 3 for calling the BiasLayerTest obj's underlying member method code with example usage: obj.testTrainableVariables() without return types