code: def test_nested_list(self):
      a, b, y_true = self._get_raw_data()
      rf = [a, b]
  
      target = _get_raw_MetricFrame()
      msg = "Feature lists must be of scalar types"
      with pytest.raises(ValueError) as execInfo:
          _ = target._process_features("SF", rf, y_true)
      assert execInfo.value.args[0] == msg
  
imports: import numpy
  import pandas
  import pytest
  import fairlearn.metrics
  from .utils import _get_raw_MetricFrame
label_desc: Use image node_id 3 for calling the TestTwoFeatures obj's underlying member method code with example usage: obj.test_nested_list() without return types