code: def test_merge_hparams(self):
      params = phoenix._merge_hparams(
          hp.HParams(learning_rate=1, untouched=4),
          hp.HParams(learning_rate=2, new_param=3),
      )
      self.assertEqual(params.learning_rate, 2)
      self.assertEqual(params.untouched, 4)
      self.assertEqual(params.new_param, 3)
  
imports: import os
  from absl import flags
  from absl.testing import parameterized
  from model_search import hparam
  from model_search import loss_fns
  from model_search import phoenix
  from model_search.architecture import architecture_utils
  from model_search.metadata import mock_metadata
  from model_search.proto import phoenix_spec_pb2
  import numpy
  import tensorflow.compat.v2
  from google.protobuf import text_format
label_desc: Use image node_id 8 for calling the PhoenixTest obj's underlying member method code with example usage: obj.test_merge_hparams() without return types