code: def _rms(self, x):
      return sqrt(torch.mean(x.pow(2)))
  
imports: import torch
  import torch.optim
  from torch.nn.utils import clip_grad_norm_
  import operator
  import functools
  from copy import copy
  from math import sqrt
  import types
  import os
  import importlib
  from onmt.utils.misc import fn_args
label_desc: Use image node_id 5 for calling the AdaFactor obj's underlying member method code with example usage: obj._rms(x) and returns: sqrt