code: def mean(self) -> float:
      return self._mean
  
file_path: ray/python/ray/data/_internal/size_estimator.py
imports: from typing import Any, List
  import ray
  from ray import cloudpickle
label_desc: Use image node_id 4 for calling the RunningMean obj's underlying member method code with example usage: obj.mean() and returns: self