code: def test_map_defaultdict_ignore_na():
      # GH#47527
      mapping = defaultdict(int, {1: 10, np.nan: 42})
      ser = Series([1, np.nan, 2])
      result = ser.map(mapping)
      expected = Series([10, 42, 0])
      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 30 for calling a global function with example usage: test_map_defaultdict_ignore_na() without return types