code: def test_sort_values_with_nulls(data, by, ascending, na_position):
      np.random.seed(0)
      cp.random.seed(0)
      df = cudf.DataFrame(data)
      ddf = dd.from_pandas(df, npartitions=5)
  
      with dask.config.set(scheduler="single-threaded"):
          got = ddf.sort_values(
              by=by, ascending=ascending, na_position=na_position
          )
          expect = df.sort_values(
              by=by, ascending=ascending, na_position=na_position
          )
  
      # cudf ordering for nulls is non-deterministic
      dd.assert_eq(got[by], expect[by], check_index=False)
  
file_path: cudf/python/dask_cudf/dask_cudf/tests/test_sort.py
imports: import cupy
  import numpy
  import pytest
  import dask
  from dask import dataframe
  import cudf
  import dask_cudf
label_desc: Use image node_id 4 for calling a global function with example usage: test_sort_values_with_nulls(data, by, ascending, na_position) without return types