code: def _add_noise(self, single_action, single_action_space):
      if isinstance(
          single_action_space, gym.spaces.Box
      ) and single_action_space.dtype.name.startswith("float"):
          single_action += (
              np.random.randn(*single_action.shape)
              * self.action_noise_std
          )
      return single_action
  
imports: from typing import Optional
  import gymnasium
  import numpy
  import tree
  import ray
  import ray.experimental.tf_utils
  from ray.rllib.models import ModelCatalog
  from ray.rllib.policy.policy import Policy
  from ray.rllib.policy.sample_batch import SampleBatch
  from ray.rllib.utils import deprecation_warning
  from ray.rllib.utils.annotations import override
  from ray.rllib.utils.filter import get_filter
  from ray.rllib.utils.framework import try_import_tf
  from ray.rllib.utils.spaces.space_utils import get_base_struct_from_space, unbatch
label_desc: Use image node_id 4 for calling the ESTFPolicy obj's underlying member method code with example usage: obj._add_noise(single_action, single_action_space) and returns: single_action