code: def test_tf2_image_enumerated_shapes(backend):
      keras_model = tf.keras.applications.MobileNetV2(
          input_shape=(
              None,
              None,
              3,
          ),
          classes=1000,
          include_top=False,
      )
      input_shapes = ct.EnumeratedShapes(
          shapes=[(1, 192, 192, 3), (1, 224, 224, 3)]
      )
      image_input = ct.ImageType(
          shape=input_shapes, bias=[-1, -1, -1], scale=1 / 127
      )
      model = ct.convert(
          keras_model, inputs=[image_input], convert_to=backend[0]
      )
      assert model is not None
      spec = model.get_spec()
      assert (
          len(
              spec.description.input[
                  0
              ].type.imageType.enumeratedSizes.sizes
          )
          == 2
      )
  
imports: import itertools
  import os
  import platform
  from os import chdir, getcwd
  from shutil import rmtree
  from tempfile import mkdtemp
  import numpy
  import pytest
  import coremltools
  from coremltools.converters.mil.frontend.tensorflow.test.test_tf_conversion_api import TestInputOutputConversionAPI
  from coremltools.converters.mil.frontend.tensorflow.test.test_tf_conversion_api import TestiOS16DefaultIODtype
  from coremltools.converters.mil.mil import types
  from coremltools.converters.mil.testing_reqs import backends
  import tensorflow
  from tensorflow import keras
  from tensorflow.keras import layers
label_desc: Use image node_id 4 for calling the TestTF2FlexibleInput obj's underlying member method code with example usage: obj.test_tf2_image_enumerated_shapes(backend) without return types