code: def test_exclusive_nat_column_indexing(self):
      # GH 38025
      # test multi indexing when one column exclusively contains NaT values
      df = DataFrame(
          {
              "a": [pd.NaT, pd.NaT, pd.NaT, pd.NaT],
              "b": ["C1", "C2", "C3", "C4"],
              "c": [10, 15, np.nan, 20],
          }
      )
      df = df.set_index(["a", "b"])
      expected = DataFrame(
          {
              "c": [10, 15, np.nan, 20],
          },
          index=[
              Index([pd.NaT, pd.NaT, pd.NaT, pd.NaT], name="a"),
              Index(["C1", "C2", "C3", "C4"], name="b"),
          ],
      )
      tm.assert_frame_equal(df, expected)
  
imports: import numpy
  import pytest
  import pandas._libs.index
  from pandas.errors import PerformanceWarning
  import pandas
  from pandas import CategoricalDtype, DataFrame, Index, MultiIndex, Series
  import pandas._testing
  from pandas.core.arrays.boolean import BooleanDtype
label_desc: Use image node_id 4 for calling the TestMultiIndexBasic obj's underlying member method code with example usage: obj.test_exclusive_nat_column_indexing() without return types