code: def _common_validations(self, result, expected_name):
      assert isinstance(result, list)
      assert len(result) == 1
      sf = result[0]
      assert isinstance(sf, metrics._group_feature.GroupFeature)
      assert sf.name_ == expected_name
      assert np.array_equal(sf.classes_, ["a", "b", "c"])
  
imports: import numpy
  import pandas
  import pytest
  import fairlearn.metrics
  from .utils import _get_raw_MetricFrame
label_desc: Use image node_id 2 for calling the TestSingleFeature obj's underlying member method code with example usage: obj._common_validations(result, expected_name) without return types