code: def _image_uri(tf_version, py_version):
      return IMAGE_URI_FORMAT_STRING.format(
          REGION, tf_version, py_version
      )
  
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 2 for calling a global function with example usage: _image_uri(tf_version, py_version) and returns: IMAGE_URI_FORMAT_STRING