code: def test_very_short_crossfade_mask_pair(self):
      fade_in, fade_out = get_crossfade_mask_pair(2)
      assert_array_almost_equal(
          fade_in, np.array([0.0, 1.0], dtype=np.float32)
      )
      assert_array_almost_equal(
          fade_out, np.array([1.0, 0.0], dtype=np.float32)
      )
  
imports: from copy import deepcopy
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from audiomentations import Gain, AdjustDuration, RepeatPart, Shift
  from audiomentations.core.utils import get_crossfade_mask_pair
  from tests.test_filter_transforms import get_chirp_test
label_desc: Use image node_id 18 for calling the TestRepeatPart obj's underlying member method code with example usage: obj.test_very_short_crossfade_mask_pair() without return types