code: def test_combine_metric_fns(self):
      # Force graph mode
      with tf.compat.v1.Graph().as_default():
  
          def metric_fn_1(labels, predictions, weights=None):
              del labels
              del predictions
              del weights
              one = tf.constant(1, dtype=tf.int32)
              return {"foo1": (one, one)}
  
          def metric_fn_2(labels, predictions, weights=None):
              del labels
              del predictions
              del weights
              two = tf.constant(2, dtype=tf.int32)
              return {"foo2": (two, two)}
  
          metric_fn_combined = metric_fns.combine_metric_fns(
              [metric_fn_1, metric_fn_2]
          )
          metrics_dict = metric_fn_combined(None, None)
  
          with self.test_session() as sess:
              self.assertEqual(1, sess.run(metrics_dict["foo1"][1]))
              self.assertEqual(2, sess.run(metrics_dict["foo2"][1]))
  
file_path: model_search/model_search/metric_fns_test.py
imports: from absl.testing import parameterized
  from model_search import metric_fns
  import numpy
  import tensorflow.compat.v2
label_desc: Use image node_id 6 for calling the MetricFnsTest obj's underlying member method code with example usage: obj.test_combine_metric_fns() and returns: dict, dict