code: def test_subclass_iterrows(self):
      # GH 13977
      df = tm.SubclassedDataFrame({"a": [1]})
      for i, row in df.iterrows():
          assert isinstance(row, tm.SubclassedSeries)
          tm.assert_series_equal(row, df.loc[i])
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestDataFrameSubclassing obj's underlying member method code with example usage: obj.test_subclass_iterrows() without return types