code: def test_custom_image(sagemaker_session):
      custom_image = "tensorflow:latest"
      tf = _build_tf(sagemaker_session, image_uri=custom_image)
      assert custom_image == tf.training_image_uri()
  
imports: from __future__ import absolute_import
  import json
  import logging
  import os
  from mock import patch, Mock, MagicMock
  from packaging import version
  import pytest
  from sagemaker.estimator import _TrainingJob
  from sagemaker.session_settings import SessionSettings
  from sagemaker.tensorflow import TensorFlow
  from sagemaker.instance_group import InstanceGroup
  from sagemaker.workflow.parameters import ParameterString, ParameterBoolean
  from tests.unit import DATA_DIR
label_desc: Use image node_id 17 for calling a global function with example usage: test_custom_image(sagemaker_session) without return types