code: def test_add_ragged_fields_single_level_sequence(self, dtype):
      # Single level sequence
      example_data = [
          [1, 2],
          [2, 3],
          [4, 5],
      ]
      tensor_info = feature_lib.TensorInfo(
          shape=(
              None,
              2,
          ),
          dtype=dtype,
          sequence_rank=1,
      )
      out = example_serializer._add_ragged_fields(
          example_data, tensor_info
      )
      self.assertAllEqual(
          out[0],
          [
              [1, 2],
              [2, 3],
              [4, 5],
          ],
      )
      self.assertEqual(out[1], tensor_info)
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import example_serializer
  from tensorflow_datasets.core.features import feature
  from tensorflow_datasets.core.utils import py_utils
label_desc: Use image node_id 9 for calling the ExampleSerializerTest obj's underlying member method code with example usage: obj.test_add_ragged_fields_single_level_sequence(dtype) without return types