code: def _common_validations(self, result, expected_names):
      assert isinstance(result, list)
      assert len(result) == 2
      for i in range(2):
          assert isinstance(
              result[i], metrics._group_feature.GroupFeature
          )
          assert result[i].name_ == expected_names[i]
      assert np.array_equal(result[0].classes_, ["a", "b", "c"])
      assert np.array_equal(result[1].classes_, [5, 6])
  
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 TestTwoFeatures obj's underlying member method code with example usage: obj._common_validations(result, expected_names) without return types