code: def test_roundtrip_backend_dispatch(tmpdir):
      # Test ddf.read_parquet cudf-backend dispatch
      tmpdir = str(tmpdir)
      ddf.to_parquet(tmpdir, engine="pyarrow")
      with dask.config.set({"dataframe.backend": "cudf"}):
          ddf2 = dd.read_parquet(tmpdir, index=False)
      assert isinstance(ddf2, dask_cudf.DataFrame)
      dd.assert_eq(ddf.reset_index(drop=False), ddf2)
  
imports: import glob
  import math
  import os
  import numpy
  import pandas
  import pytest
  import dask
  from dask import dataframe
  from dask.utils import natural_sort_key
  import cudf
  import dask_cudf
label_desc: Use image node_id 1 for calling a global function with example usage: test_roundtrip_backend_dispatch(tmpdir) without return types