code: def update(self, val: float, n: int = 1):
      """
      Update loss tracker
      :param val: Loss value to add to tracker
      :param n: Number of elements contributing to val
      """
      self.val = val
      self.sum += val * n
      self.count += n
      self.avg = self.sum / self.count
  
label_desc: Use image node_id 3 for calling the LossMeter obj's underlying member method code with example usage: obj.update(val, n) without return types