code: def test_errors(self):
      stepm = StepM(self.benchmark, self.models, size=0.10)
      with pytest.raises(RuntimeError):
          stepm.superior_models
  
imports: from typing import NamedTuple
  import numpy
  from numpy import linspace
  from numpy.random import RandomState
  from numpy.testing import assert_allclose, assert_equal
  import pandas
  from pandas.testing import assert_frame_equal, assert_series_equal
  import pytest
  import scipy.stats
  from arch.bootstrap import CircularBlockBootstrap, MovingBlockBootstrap, StationaryBootstrap
  from arch.bootstrap.multiple_comparison import MCS, SPA, StepM
label_desc: Use image node_id 7 for calling the TestStepM obj's underlying member method code with example usage: obj.test_errors() without return types