code: def test_saved_model_from_simple_save(self, backend):
      with tf.compat.v1.Session() as sess:
          x = tf.placeholder(shape=(1, 3, 5), dtype=tf.float32)
          y = tf.nn.relu(x)
          inputs = {"x": x}
          outputs = {"y": y}
          tf.compat.v1.saved_model.simple_save(
              sess, self.saved_model_dir, inputs, outputs
          )
      mlmodel = converter.convert(
          self.saved_model_dir, convert_to=backend[0]
      )
      assert mlmodel is not None
  
imports: import os
  import shutil
  import tempfile
  import numpy
  import pytest
  import coremltools
  import coremltools.converters
  import coremltools.proto.FeatureTypes_pb2
  from coremltools import EnumeratedShapes, ImageType, RangeDim, TensorType
  from coremltools._deps import _HAS_TF_1, _IS_MACOS, MSG_TF1_NOT_FOUND
  from coremltools.converters.mil.frontend.tensorflow.converter import TFConverter
  from coremltools.converters.mil.frontend.tensorflow.test.testing_utils import TensorFlowBaseTest, get_tf_keras_io_names, make_tf_graph
  from coremltools.converters.mil.testing_reqs import backends
  from coremltools.converters.mil.testing_utils import random_gen
label_desc: Use image node_id 5 for calling the TestTf1ModelFormats obj's underlying member method code with example usage: obj.test_saved_model_from_simple_save(backend) without return types