code: def test_n(self, mock_main, mock_initial):
      mock_main.return_value = [iaa.Add(1), iaa.Add(2), iaa.Add(4)]
      mock_initial.return_value = []
  
      img = np.zeros((1, 1, 3), dtype=np.uint8)
      expected = {
          0: [0],
          1: [1, 2, 4],
          2: [1 + 1, 1 + 2, 1 + 4, 2 + 2, 2 + 4, 4 + 4],
      }
  
      for n in [0, 1, 2]:
          with self.subTest(n=n):
              aug = iaa.RandAugment(n=n)
              img_aug = aug(image=img)
              assert img_aug[0, 0, 0] in expected[n]
  
file_path: imgaug/test/augmenters/test_collections.py
imports: from __future__ import print_function, division, absolute_import
  import sys
  import numpy
  from imgaug import augmenters
  from imgaug.testutils import reseed, runtest_pickleable_uint8_img
label_desc: Use image node_id 2 for calling the TestRandAugment obj's underlying member method code with example usage: obj.test_n(mock_main, mock_initial) without return types