code: def test_2lvl_sequences_mixed(self):
      # Mix of sequence and non-sequence
      self.assertFeature(
          feature=feature_lib.Sequence(
              {
                  "a": feature_lib.Sequence(np.int32),
                  "b": np.int32,
              }
          ),
          shape={
              "a": (None, None),
              "b": (None,),
          },
          dtype={
              "a": np.int32,
              "b": np.int32,
          },
          tests=[
              testing.FeatureExpectationItem(
                  value={
                      "a": [[1, 1, 1], [], [3, 3]],
                      "b": [1, 2, 3],
                  },
                  expected={
                      "a": [[1, 1, 1], [], [3, 3]],
                      "b": [1, 2, 3],
                  },
                  expected_np={
                      "a": [[1, 1, 1], [], [3, 3]],
                      "b": [1, 2, 3],
                  },
              ),
          ],
      )
  
imports: import numpy
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import features
label_desc: Use image node_id 5 for calling the SequenceDictFeatureTest obj's underlying member method code with example usage: obj.test_2lvl_sequences_mixed() without return types