code: def test_map_categorical_na_action(na_action, expected):
      dtype = pd.CategoricalDtype(list("DCBA"), ordered=True)
      values = pd.Categorical(list("AB") + [np.nan], dtype=dtype)
      s = Series(values, name="XX")
      result = s.map(str, na_action=na_action)
      tm.assert_series_equal(result, expected)
  
imports: from collections import Counter, defaultdict
  from decimal import Decimal
  import math
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series, bdate_range, date_range, isna, timedelta_range
  import pandas._testing
label_desc: Use image node_id 41 for calling a global function with example usage: test_map_categorical_na_action(na_action, expected) without return types