code: def test_basic_functionality(self):
      # basic functionality test
      aug = iaa.FastSnowyLandscape(
          lightness_threshold=100, lightness_multiplier=2.0
      )
      image = (
          np.arange(0, 6 * 6 * 3).reshape((6, 6, 3)).astype(np.uint8)
      )
      image_hls = cv2.cvtColor(image, cv2.COLOR_RGB2HLS)
      mask = image_hls[..., 1] < 100
      expected = np.copy(image_hls).astype(np.float32)
      expected[..., 1][mask] *= 2.0
      expected = np.clip(np.round(expected), 0, 255).astype(np.uint8)
      expected = cv2.cvtColor(expected, cv2.COLOR_HLS2RGB)
      observed = aug.augment_image(image)
      assert np.array_equal(observed, expected)
  
imports: from __future__ import print_function, division, absolute_import
  import sys
  import numpy
  import cv2
  import imgaug
  from imgaug import augmenters
  from imgaug import parameters
  from imgaug.testutils import reseed, runtest_pickleable_uint8_img, is_parameter_instance
label_desc: Use image node_id 3 for calling the TestFastSnowyLandscape obj's underlying member method code with example usage: obj.test_basic_functionality() without return types