code: def test_contains_none() -> None:
      s = pl.Series([1, None])
      result = None in s
      assert result is True
  
      s = pl.Series([1, 2])
      assert (None in s) is False
  
imports: from __future__ import annotations
  from datetime import date
  from typing import Any
  import pytest
  import polars
label_desc: Use image node_id 2 for calling a global function with example usage: test_contains_none() without return types