code: def __init__(self):
      self._weight = 0
      self._mean = 0
  
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 1 to create a new RunningMean object  with example: obj = RunningMean()