class_docstr: Class for global accumulation state. add_stats gets reduced.
code: def add_stats(self, dst, src):
      for k, v in dst.items():
          v += src[k]
      return dst
  
imports: import copy
  import dataclasses
  import logging
  import torch
  import moolib
label_desc: Use image node_id 2 for calling the GlobalStatsAccumulator obj's underlying member method code with example usage: obj.add_stats(dst, src) and returns: dst