code: def test_categorical_as_known():
      df = dgd.from_cudf(
          DataFrame({"col_1": [0, 1, 2, 3]}), npartitions=2
      )
      df["col_1"] = df["col_1"].astype("category")
      actual = df["col_1"].cat.as_known()
  
      pdf = dd.from_pandas(
          pd.DataFrame({"col_1": [0, 1, 2, 3]}), npartitions=2
      )
      pdf["col_1"] = pdf["col_1"].astype("category")
      expected = pdf["col_1"].cat.as_known()
      dd.assert_eq(expected, actual)
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_series_equal
  from dask import dataframe
  from cudf import DataFrame, Series, date_range
  from cudf.testing._utils import assert_eq, does_not_raise
  import dask_cudf
label_desc: Use image node_id 18 for calling a global function with example usage: test_categorical_as_known() without return types