code: def test_fill_null_f32_with_lit() -> None:
      # ensure the literal integer does not upcast the f32 to an f64
      df = pl.DataFrame({"a": [1.1, 1.2]}, schema=[("a", pl.Float32)])
      assert df.fill_null(value=0).dtypes == [pl.Float32]
  
imports: from __future__ import annotations
  from collections import OrderedDict
  from datetime import date, timedelta
  from typing import Any, Iterator, Mapping
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 20 for calling a global function with example usage: test_fill_null_f32_with_lit() without return types