code: def update_target(self, tau=None):
      if tau is not None:
          self.get_session().run(
              self.update_target_vars, {self.tau: tau}
          )
      else:
          self.get_session().run(self.update_target_vars)
  
imports: import logging
  import numpy
  from gymnasium.spaces import Box, Discrete
  from ray.rllib.algorithms.dqn.dqn_tf_policy import minimize_and_clip
  from ray.rllib.evaluation.postprocessing import adjust_nstep
  from ray.rllib.models import ModelCatalog
  from ray.rllib.policy.policy import Policy
  from ray.rllib.policy.sample_batch import SampleBatch
  from ray.rllib.policy.tf_policy import TFPolicy
  from ray.rllib.utils.annotations import override
  from ray.rllib.utils.error import UnsupportedSpaceException
  from ray.rllib.utils.framework import try_import_tf, try_import_tfp
  from ray.rllib.utils.metrics.learner_info import LEARNER_STATS_KEY
label_desc: Use image node_id 13 for calling the MADDPGTFPolicy obj's underlying member method code with example usage: obj.update_target(tau) without return types