code: def test_str_series_roundtrip():
      with dask_cuda.LocalCUDACluster(n_workers=1) as cluster:
          with Client(cluster):
              expected = cudf.Series(["hi", "hello", None])
              dask_series = dask_cudf.from_cudf(expected, npartitions=2)
  
              actual = dask_series.compute()
              assert_eq(actual, expected)
  
file_path: cudf/python/dask_cudf/dask_cudf/tests/test_distributed.py
imports: import numba.cuda
  import pytest
  import dask
  from dask import dataframe
  from dask.distributed import Client
  from distributed.utils_test import cleanup, loop, loop_in_thread
  import cudf
  from cudf.testing._utils import assert_eq
  import dask_cudf
label_desc: Use image node_id 5 for calling a global function with example usage: test_str_series_roundtrip() without return types