code: def test_model_fn(self, problem, input_shape, hparams, label_shape):
      # Force graph mode
      with tf.compat.v1.Graph().as_default():
          instance = self._create_phoenix_instance(problem, input_shape)
          features = {
              "zeros": tf.zeros(input_shape),
              "lengths": tf.ones([20]),
          }
          labels = tf.ones(label_shape, dtype=tf.int32)
          run_config = tf.estimator.RunConfig(
              model_dir=self.get_temp_dir() + "/1"
          )
  
          model_fn = instance._make_model_fn(
              run_config, train_steps=100
          )
          _ = model_fn(
              features, labels, tf.estimator.ModeKeys.TRAIN, hparams
          )
  
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 5 for calling the PhoenixTest obj's underlying member method code with example usage: obj.test_model_fn(problem, input_shape, hparams, label_shape) without return types