code: def test_astype_bool_missing_to_categorical(self):
      # GH-19182
      ser = Series([True, False, np.nan])
      assert ser.dtypes == np.object_
  
      result = ser.astype(CategoricalDtype(categories=[True, False]))
      expected = Series(
          Categorical([True, False, np.nan], categories=[True, False])
      )
      tm.assert_series_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  from importlib import reload
  import string
  import sys
  import numpy
  import pytest
  from pandas._libs.tslibs import iNaT
  import pandas.util._test_decorators
  from pandas import NA, Categorical, CategoricalDtype, DatetimeTZDtype, Index, Interval, NaT, Series, Timedelta, Timestamp, cut, date_range, to_datetime
  import pandas._testing
label_desc: Use image node_id 5 for calling the TestAstypeCategorical obj's underlying member method code with example usage: obj.test_astype_bool_missing_to_categorical() without return types