code: def forward(self, input):
      return (input - self.mean) * self.invstddev
  
imports: import json
  import math
  from abc import ABC, abstractmethod
  from dataclasses import dataclass
  from functools import partial
  from typing import Callable, List, Tuple
  import torch
  import torchaudio
  from torchaudio._internal import module_utils
  from torchaudio.models import emformer_rnnt_base, RNNT, RNNTBeamSearch
label_desc: Use image node_id 2 for calling the _GlobalStatsNormalization obj's underlying member method code with example usage: obj.forward(input) and returns: unknown