code: def test_map_elements_skip_nulls() -> None:
      some_map = {None: "a", 1: "b"}
      s = pl.Series([None, 1])
  
      assert s.map_elements(lambda x: some_map[x]).to_list() == [
          None,
          "b",
      ]
      assert s.map_elements(
          lambda x: some_map[x], skip_nulls=False
      ).to_list() == [
          "a",
          "b",
      ]
  
imports: from __future__ import annotations
  import json
  from datetime import date, datetime, timedelta
  import numpy
  import pytest
  import polars
  from polars.exceptions import PolarsInefficientMapWarning
  from polars.testing import assert_frame_equal
label_desc: Use image node_id 10 for calling a global function with example usage: test_map_elements_skip_nulls() without return types