code: def build(self, *args, **kwargs):
      self.var = common.create_variable(
          "trainable_variable", dtype=tf.float32, trainable=True
      )
      self.state = common.create_variable(
          "state", dtype=tf.float32, trainable=False
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import tensorflow
  import tensorflow_probability
  from tf_agents import specs
  from tf_agents.distributions import utils
  from tf_agents.keras_layers import rnn_wrapper
  from tf_agents.networks import network
  from tf_agents.utils import common
label_desc: Use image node_id 2 for calling the MockStateFullNetwork obj's underlying member method code with example usage: obj.build() without return types