code: def __iadd__(self, other):
      if isinstance(other, StatMean):
          self.value += other.value
          self.n += other.n
      else:
          self.value += other
          self.n += 1
      return self
  
imports: import copy
  import dataclasses
  import logging
  import torch
  import moolib
label_desc: Use image node_id 3 for calling the StatMean obj's underlying member method code with example usage: obj.__iadd__(other) and returns: self