code: def test_add_sequence_feature_column():
      df = pd.DataFrame([1, 2, 3, 4, 5], columns=["x"])
  
      add_sequence_feature_column(df, "x", 2)
      assert df.equals(
          pd.DataFrame(
              [
                  [1, "1 2"],
                  [2, "1 2"],
                  [3, "1 2"],
                  [4, "2 3"],
                  [5, "3 4"],
              ],
              columns=["x", "x_feature"],
          )
      )
  
      add_sequence_feature_column(df, "x", 1)
      assert df.equals(
          pd.DataFrame(
              [
                  [1, "1"],
                  [2, "1"],
                  [3, "2"],
                  [4, "3"],
                  [5, "4"],
              ],
              columns=["x", "x_feature"],
          )
      )
  
      df = pd.DataFrame([1, 2, 3, 4, 5], columns=["x"])
  
      add_sequence_feature_column(df, "y", 2)
      assert df.equals(pd.DataFrame([1, 2, 3, 4, 5], columns=["x"]))
  
imports: import functools
  import json
  import logging
  import numpy
  import pandas
  import pytest
  from fsspec.config import conf
  from ludwig.api import LudwigModel
  from ludwig.data.cache.types import CacheableDataframe
  from ludwig.data.dataset_synthesizer import build_synthetic_dataset_df
  from ludwig.utils.data_utils import add_sequence_feature_column, figure_data_format_dataset, get_abs_path, hash_dict, NumpyEncoder, PANDAS_DF, read_csv, read_html, read_parquet, sanitize_column_names, use_credentials
  from tests.integration_tests.utils import private_param
label_desc: Use image node_id 1 for calling a global function with example usage: test_add_sequence_feature_column() without return types