code: def var(self):
      return (
          self.std_array / (self.num_pushes - 1)
          if self.num_pushes > 1
          else np.square(self.mean_array)
      )
  
imports: import logging
  import threading
  import numpy
  import tree
  from ray.rllib.utils.annotations import DeveloperAPI
  from ray.rllib.utils.deprecation import Deprecated
  from ray.rllib.utils.numpy import SMALL_NUMBER
  from ray.rllib.utils.typing import TensorStructType
  from ray.rllib.utils.serialization import _serialize_ndarray, _deserialize_ndarray
  from ray.rllib.utils.deprecation import deprecation_warning
label_desc: Use image node_id 8 for calling the RunningStat obj's underlying member method code with example usage: obj.var() and returns: unknown