code: def test_longley(self):
      data = getattr(sm.datasets.longley, self.load_method)()
      df = pdml.ModelFrame(data)
      self.assertEqual(df.shape, (16, 7))
      self.assertEqual(df.target_name, "TOTEMP")
      tm.assert_index_equal(df.data.columns, pd.Index(data.exog_name))
  
imports: import pytest
  import pandas
  import statsmodels.api
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 10 for calling the TestStatsModelsDatasets obj's underlying member method code with example usage: obj.test_longley() without return types