code: def test_combine_first_with_asymmetric_other(self, val):
      # see gh-20699
      df1 = DataFrame({"isNum": [val]})
      df2 = DataFrame({"isBool": [True]})
  
      res = df1.combine_first(df2)
      exp = DataFrame({"isBool": [True], "isNum": [val]})
  
      tm.assert_frame_equal(res, exp)
  
imports: from datetime import datetime
  import numpy
  import pytest
  from pandas.core.dtypes.cast import find_common_type
  from pandas.core.dtypes.common import is_dtype_equal
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 17 for calling the TestDataFrameCombineFirst obj's underlying member method code with example usage: obj.test_combine_first_with_asymmetric_other(val) without return types