code: def test_3lvl_sequence(self):
      self.assertFeature(
          feature=feature_lib.Sequence(
              feature_lib.Sequence(
                  feature_lib.Sequence(np.int32),
                  length=3,
              ),
          ),
          shape=(None, 3, None),
          dtype=np.int32,
          test_tensor_spec=False,  # TODO(b/227584124): doesn't work
          tests=[
              testing.FeatureExpectationItem(
                  value=[
                      [[1, 2, 3], [], [4, 5]],
                      [[10, 11], [12, 13], [14]],
                  ],
                  expected=[
                      [[1, 2, 3], [], [4, 5]],
                      [[10, 11], [12, 13], [14]],
                  ],
                  expected_np=[
                      [[1, 2, 3], [], [4, 5]],
                      [[10, 11], [12, 13], [14]],
                  ],
              ),
              testing.FeatureExpectationItem(
                  value=[
                      [[1, 2, 3], [4, 5]],  # < Only 2 instead of 3
                      [[10, 11], [12, 13], [14]],
                  ],
                  raise_cls=ValueError,
                  raise_cls_np=ValueError,
                  raise_msg="Input sequence length do not match",
              ),
          ],
      )
  
imports: import numpy
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import features
label_desc: Use image node_id 8 for calling the SequenceDictFeatureTest obj's underlying member method code with example usage: obj.test_3lvl_sequence() without return types