code: def test_polarity_inversion(self):
      samples = np.array(
          [1.0, 0.5, -0.25, -0.125, 0.0], dtype=np.float32
      )
      sample_rate = 16000
  
      augment = Compose([PolarityInversion(p=1.0)])
      inverted_samples = augment(
          samples=samples, sample_rate=sample_rate
      )
      assert_almost_equal(
          inverted_samples,
          np.array([-1.0, -0.5, 0.25, 0.125, 0.0], dtype=np.float32),
      )
      assert inverted_samples.dtype == np.float32
  
imports: import numpy
  from numpy.testing import assert_almost_equal
  from audiomentations import PolarityInversion, Compose
label_desc: Use image node_id 1 for calling the TestPolarityInversion obj's underlying member method code with example usage: obj.test_polarity_inversion() without return types