def METHOD_NAME():
    ts_df = DUMMY_VARIABLE_LENGTH_TS_DATAFRAME.copy()
    splitter = MultiWindowSplitter()
    ts_df_with_suffix = splitter._append_suffix_to_item_id(ts_dataframe=ts_df, suffix="_[None:None]")
    assert ts_df.values.base is ts_df_with_suffix.values.base