docstr: Test that dereverb can be initialized and can process audio.
          
docstr_tok: ["Test","that","dereverb","can","be","initialized","and","can","process","audio","."]
code: def test_mask_based_dereverb_init(
      self, num_channels: int, filter_length: int, delay: int
  ):
      """Test that dereverb can be initialized and can process audio."""
      num_examples = 10
      batch_size = 8
      num_subbands = 15
      num_frames = 21
      num_iterations = 2
  
      input_size = (batch_size, num_subbands, num_frames, num_channels)
  
      dereverb = MaskBasedDereverbWPE(
          filter_length=filter_length,
          prediction_delay=delay,
          num_iterations=num_iterations,
      )
  
      for n in range(num_examples):
          # multi-channel input
          x = torch.randn(input_size) + 1j * torch.randn(input_size)
          # random input_length
          x_length = torch.randint(1, num_frames, (batch_size,))
          # multi-channel mask
          mask = torch.rand(input_size)
  
          # UUT
          y, y_length = dereverb(
              input=x, input_length=x_length, mask=mask
          )
  
          assert (
              y.shape == x.shape
          ), "Output shape not matching, example {n}"
          assert torch.equal(
              y_length, x_length
          ), "Length not matching, example {n}"
  
imports: import importlib
  from typing import Optional
  import numpy
  import pytest
  import torch
  from nemo.collections.asr.modules.audio_modules import MaskBasedDereverbWPE, MaskEstimatorFlexChannels, MaskEstimatorGSS, MaskReferenceChannel, SpectrogramToMultichannelFeatures, WPEFilter
  from nemo.collections.asr.modules.audio_preprocessing import AudioToSpectrogram
  from nemo.collections.asr.parts.utils.audio_utils import convmtx_mc_numpy
  from nemo.utils import logging
label_desc: Use image node_id 3 for calling the TestMaskBasedDereverb obj's underlying member method code with example usage: obj.test_mask_based_dereverb_init(num_channels, filter_length, delay) without return types