code: def test_combine_first_same_as_in_update(self):
      # gh 3016 (same as in update)
      df = DataFrame(
          [[1.0, 2.0, False, True], [4.0, 5.0, True, False]],
          columns=["A", "B", "bool1", "bool2"],
      )
  
      other = DataFrame([[45, 45]], index=[0], columns=["A", "B"])
      result = df.combine_first(other)
      tm.assert_frame_equal(result, df)
  
      df.loc[0, "A"] = np.nan
      result = df.combine_first(other)
      df.loc[0, "A"] = 45
      tm.assert_frame_equal(result, df)
  
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 4 for calling the TestDataFrameCombineFirst obj's underlying member method code with example usage: obj.test_combine_first_same_as_in_update() without return types