code: def test_apply_time_mask_multichannel(self):
      sample_len = 1024
      samples_in = np.random.normal(0, 1, size=(2, sample_len)).astype(
          np.float32
      )
      sample_rate = 16000
      augmenter = TimeMask(min_band_part=0.2, max_band_part=0.5, p=1.0)
  
      samples_out = augmenter(
          samples=samples_in, sample_rate=sample_rate
      )
      assert samples_out.dtype == np.float32
      assert samples_out.shape == samples_in.shape
  
      std_in = np.mean(np.abs(samples_in))
      std_out = np.mean(np.abs(samples_out))
      assert std_out < std_in
  
file_path: audiomentations/tests/test_time_mask.py
imports: import numpy
  import pytest
  from audiomentations import TimeMask, Compose
label_desc: Use image node_id 3 for calling the TestTimeMask obj's underlying member method code with example usage: obj.test_apply_time_mask_multichannel() without return types