code: def test_only_per_feature_override(self):
      m = example_weight_map.ExampleWeightMap(
          per_feature_override={
              types.FeaturePath(["foo"]): "w1",
          }
      )
      self.assertEqual("w1", m.get(types.FeaturePath(["foo"])))
      self.assertIsNone(m.get(types.FeaturePath(["feature"])))
      self.assertEqual(m.all_weight_features(), frozenset(["w1"]))
  
file_path: data-validation/tensorflow_data_validation/utils/example_weight_map_test.py
imports: from absl.testing import absltest
  from tensorflow_data_validation import types
  from tensorflow_data_validation.utils import example_weight_map
label_desc: Use image node_id 4 for calling the ExampleWeightMapTest obj's underlying member method code with example usage: obj.test_only_per_feature_override() without return types