code: def test_AudioToMelSpectrogramPreprocessor_batch(self):
      # Test 1 that should test the pure stft implementation as much as possible
      instance1 = modules.AudioToMelSpectrogramPreprocessor(
          normalize="per_feature", dither=0, pad_to=0
      )
  
      # Ensure that the two functions behave similarily
      for _ in range(10):
          input_signal = torch.randn(size=(4, 512))
          length = torch.randint(low=161, high=500, size=[4])
  
          with torch.no_grad():
              # batch size 1
              res_instance, length_instance = [], []
              for i in range(input_signal.size(0)):
                  res_ins, length_ins = instance1(
                      input_signal=input_signal[i : i + 1],
                      length=length[i : i + 1],
                  )
                  res_instance.append(res_ins)
                  length_instance.append(length_ins)
  
              res_instance = torch.cat(res_instance, 0)
              length_instance = torch.cat(length_instance, 0)
  
              # batch size 4
              res_batch, length_batch = instance1(
                  input_signal=input_signal, length=length
              )
  
          assert res_instance.shape == res_batch.shape
          assert length_instance.shape == length_batch.shape
          diff = torch.mean(torch.abs(res_instance - res_batch))
          assert diff <= 1e-3
          diff = torch.max(torch.abs(res_instance - res_batch))
          assert diff <= 1e-3
  
imports: import pytest
  import torch
  from omegaconf import OmegaConf
  from nemo.collections.asr import modules
  from nemo.collections.asr.parts.utils.rnnt_utils import Hypothesis
  from nemo.core.utils import numba_utils
  from nemo.core.utils.numba_utils import __NUMBA_MINIMUM_VERSION__
  from nemo.utils import config_utils, logging
label_desc: Use image node_id 2 for calling the TestASRModulesBasicTests obj's underlying member method code with example usage: obj.test_AudioToMelSpectrogramPreprocessor_batch() without return types