code: def test_slice_reverse(df_strings):
      """
      Test output on a reverse slice
      """
      actual = df_strings.select_columns(slice("code2", "code", -1))
      expected = df_strings.loc[
          :,
          [
              "code2",
              "code1",
              "code",
          ],
      ]
  
      assert_frame_equal(actual, expected)
  
imports: import datetime
  import re
  from itertools import product
  import numpy
  import pandas
  import pytest
  from pandas.api.types import is_numeric_dtype
  from pandas.testing import assert_frame_equal
  from janitor.functions.utils import DropLabel, get_columns, patterns
label_desc: Use image node_id 24 for calling a global function with example usage: test_slice_reverse(df_strings) without return types