code: def test_flatten_with_sequence(self):
      features = Features(
          {"foo": Sequence({"bar": {"my_value": Value("int32")}})}
      )
      _features = features.copy()
      flattened_features = features.flatten()
      assert flattened_features == {
          "foo.bar": [{"my_value": Value("int32")}]
      }
      assert (
          features == _features
      ), "calling flatten shouldn't alter the current features"
  
imports: import datetime
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  import pandas
  import pyarrow
  import pytest
  from datasets import Array2D
  from datasets.arrow_dataset import Dataset
  from datasets.features import Audio, ClassLabel, Features, Image, Sequence, Value
  from datasets.features.features import _arrow_to_datasets_dtype, _cast_to_python_objects, cast_to_python_objects, encode_nested_example, generate_from_dict, string_to_arrow
  from datasets.features.translation import Translation, TranslationVariableLanguages
  from datasets.info import DatasetInfo
  from datasets.utils.py_utils import asdict
  from ..utils import require_jax, require_tf, require_torch
label_desc: Use image node_id 9 for calling the FeaturesTest obj's underlying member method code with example usage: obj.test_flatten_with_sequence() without return types