code: def test_frame_subclassing_and_slicing(self):
      # Subclass frame and ensure it returns the right class on slicing it
      # In reference to PR 9632
  
      class CustomSeries(Series):
          @property
          def _constructor(self):
              return CustomSeries
  
          def custom_series_function(self):
              return "OK"
  
      class CustomDataFrame(DataFrame):
          """
          Subclasses pandas DF, fills DF with simulation results, adds some
          custom plotting functions.
          """
  
          def __init__(self, *args, **kw) -> None:
              super().__init__(*args, **kw)
  
          @property
          def _constructor(self):
              return CustomDataFrame
  
          _constructor_sliced = CustomSeries
  
          def custom_frame_function(self):
              return "OK"
  
      data = {"col1": range(10), "col2": range(10)}
      cdf = CustomDataFrame(data)
  
      # Did we get back our own DF class?
      assert isinstance(cdf, CustomDataFrame)
  
      # Do we get back our own Series class after selecting a column?
      cdf_series = cdf.col1
      assert isinstance(cdf_series, CustomSeries)
      assert cdf_series.custom_series_function() == "OK"
  
      # Do we get back our own DF class after slicing row-wise?
      cdf_rows = cdf[1:5]
      assert isinstance(cdf_rows, CustomDataFrame)
      assert cdf_rows.custom_frame_function() == "OK"
  
      # Make sure sliced part of multi-index frame is custom class
      mcol = MultiIndex.from_tuples([("A", "A"), ("A", "B")])
      cdf_multi = CustomDataFrame([[0, 1], [2, 3]], columns=mcol)
      assert isinstance(cdf_multi["A"], CustomDataFrame)
  
      mcol = MultiIndex.from_tuples([("A", ""), ("B", "")])
      cdf_multi2 = CustomDataFrame([[0, 1], [2, 3]], columns=mcol)
      assert isinstance(cdf_multi2["A"], CustomSeries)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestDataFrameSubclassing obj's underlying member method code with example usage: obj.test_frame_subclassing_and_slicing() and returns: CustomSeries, str, CustomDataFrame, str