code: def test_categorize_nan():
      df = dd.from_pandas(
          pd.DataFrame({"A": ["a", "b", "a", float("nan")]}),
          npartitions=2,
      )
      with warnings.catch_warnings(record=True) as record:
          df.categorize().compute()
      assert not record
  
imports: from __future__ import annotations
  import contextlib
  import operator
  import warnings
  import numpy
  import pandas
  import pytest
  import dask
  import dask.dataframe
  from dask.dataframe import _compat
  from dask.dataframe._compat import PANDAS_GE_150, PANDAS_GE_200, PANDAS_GE_210, tm
  from dask.dataframe._pyarrow import to_pyarrow_string
  from dask.dataframe.core import _concat
  from dask.dataframe.utils import assert_eq, clear_known_categories, get_string_dtype, make_meta, pyarrow_strings_enabled
label_desc: Use image node_id 10 for calling a global function with example usage: test_categorize_nan() without return types