code: def test_mixup(self):
      dataset = MixUpSoftLabelDataset(
          self.siamese_dataset, self.n_class, alpha=self.alpha
      )
      for i in range(10):
          example = dataset[i]
          self._check_example(example)
      assert len(dataset) == N
  
file_path: chainercv/tests/datasets_tests/test_mixup_soft_label_dataset.py
imports: import unittest
  import numpy
  import pytest
  from chainer import testing
  from chainer.datasets import TupleDataset
  from chainercv.datasets import MixUpSoftLabelDataset
  from chainercv.datasets import SiameseDataset
  from chainercv.utils.testing.assertions.assert_is_image import assert_is_image
label_desc: Use image node_id 3 for calling the TestMixupSoftLabelDataset obj's underlying member method code with example usage: obj.test_mixup() without return types