code: def test_gpu_save_load_export(self):
      old_num_gpus = tc.config.get_num_gpus()
      gpu_options = set([old_num_gpus, 0, 1])
      for in_gpus in gpu_options:
          for out_gpus in gpu_options:
              tc.config.set_num_gpus(in_gpus)
              model = tc.activity_classifier.create(
                  self.data,
                  target=self.target,
                  session_id=self.session_id,
              )
              with test_util.TempDirectory() as filename:
                  model.save(filename)
                  model = tc.load_model(filename)
  
              filename = tempfile.NamedTemporaryFile(
                  suffix=".mlmodel"
              ).name
              model.export_coreml(filename)
  
      tc.config.set_num_gpus(old_num_gpus)
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import turicreate
  import random
  import tempfile
  import math
  import numpy
  from numbers import Number
  from .None import util
  import pytest
  from turicreate.toolkits._internal_utils import _mac_ver
  from turicreate.toolkits._main import ToolkitError
  import uuid
label_desc: Use image node_id 2 for calling the ActivityClassifierGPUTest obj's underlying member method code with example usage: obj.test_gpu_save_load_export() without return types