code: def test_struct_lit_cast() -> None:
      df = pl.DataFrame({"a": [1, 2, 3]})
      schema = {"a": pl.Int64, "b": pl.List(pl.Int64)}
  
      out = df.select(
          pl.struct(pl.col("a"), pl.lit(None).alias("b"), schema=schema)  # type: ignore[arg-type]
      ).get_column("a")
  
      expected = pl.Series(
          "a",
          [
              {"a": 1, "b": None},
              {"a": 2, "b": None},
              {"a": 3, "b": None},
          ],
          dtype=pl.Struct(
              [
                  pl.Field("a", pl.Int64),
                  pl.Field("b", pl.List(pl.Int64)),
              ]
          ),
      )
      assert_series_equal(out, expected)
  
      out = df.select(
          pl.struct([pl.col("a"), pl.lit(pl.Series([[]])).alias("b")], schema=schema)  # type: ignore[arg-type]
      ).get_column("a")
  
      expected = pl.Series(
          "a",
          [
              {"a": 1, "b": []},
              {"a": 2, "b": []},
              {"a": 3, "b": []},
          ],
          dtype=pl.Struct(
              [
                  pl.Field("a", pl.Int64),
                  pl.Field("b", pl.List(pl.Int64)),
              ]
          ),
      )
      assert_series_equal(out, expected)
  
imports: from __future__ import annotations
  from datetime import date, datetime
  from typing import TYPE_CHECKING
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 22 for calling a global function with example usage: test_struct_lit_cast() without return types