code: def test_list_null_pickle() -> None:
      df = pl.DataFrame([{"a": None}], schema={"a": pl.List(pl.Int64)})
      assert_frame_equal(df, pickle.loads(pickle.dumps(df)))
  
imports: from __future__ import annotations
  import pickle
  from datetime import date, datetime, time
  from typing import TYPE_CHECKING, Any
  import pandas
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 34 for calling a global function with example usage: test_list_null_pickle() without return types