code: def test_decimal_arithmetic() -> None:
      df = pl.DataFrame(
          {
              "a": [D("0.1"), D("10.1"), D("100.01")],
              "b": [D("20.1"), D("10.19"), D("39.21")],
          }
      )
  
      out = df.select(
          out1=pl.col("a") * pl.col("b"),
          out2=pl.col("a") + pl.col("b"),
          out3=pl.col("a") / pl.col("b"),
          out4=pl.col("a") - pl.col("b"),
      )
      assert out.dtypes == [
          pl.Decimal(precision=None, scale=2),
          pl.Decimal(precision=None, scale=2),
          pl.Decimal(precision=None, scale=2),
          pl.Decimal(precision=None, scale=2),
      ]
  
      assert out.to_dict(as_series=False) == {
          "out1": [D("2.01"), D("102.91"), D("3921.39")],
          "out2": [D("20.20"), D("20.29"), D("139.22")],
          "out3": [D("0.00"), D("0.99"), D("2.55")],
          "out4": [D("-20.00"), D("-0.09"), D("60.80")],
      }
  
imports: from __future__ import annotations
  import io
  import itertools
  from dataclasses import dataclass
  from decimal import Decimal
  from typing import Any, NamedTuple
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  import polars
  from polars.testing import assert_frame_equal
label_desc: Use image node_id 12 for calling a global function with example usage: test_decimal_arithmetic() without return types