code: def update(self, val, n=1):
      self.val = val
      self.sum += val * n
      self.count += n
      self.avg = self.sum / self.count
  
imports: import paddle
  from paddle.distributed import ParallelEnv
  import os
  import json
  from collections import defaultdict, OrderedDict
  import numpy
  from ppdet.utils.logger import setup_logger
label_desc: Use image node_id 3 for calling the AverageMeter obj's underlying member method code with example usage: obj.update(val, n) without return types