code: def test_subsets_multiindex_dtype(self):
      # GH 20757
      data = [["x", 1]]
      columns = [("a", "b", np.nan), ("a", "c", 0.0)]
      df = DataFrame(data, columns=MultiIndex.from_tuples(columns))
      expected = df.dtypes.a.b
      result = df.a.b.dtypes
      tm.assert_series_equal(result, expected)
  
imports: import datetime
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 15 for calling the TestMultiLevel obj's underlying member method code with example usage: obj.test_subsets_multiindex_dtype() without return types