code: def test_invert():
      """Test of the White Noise Augmenter."""
      X = _load_test_data()
      augmenter = aug.InvertAugmenter()
      Xt = augmenter.fit_transform(X)
      checksum = _calc_checksum(Xt)
      assert checksum == expected_checksum_invert
  
file_path: sktime/sktime/transformations/series/tests/test_augmenter.py
imports: import numpy
  import pandas
  import pytest
  from sktime.datasets import load_basic_motions
  from sktime.transformations.series import augmenter
label_desc: Use image node_id 6 for calling a global function with example usage: test_invert() without return types