code: def checkpoint_dag(checkpoint):
      @ray.remote
      def large_input():
          return np.arange(SIZE)
  
      @ray.remote
      def identity(x):
          if not utils.check_global_mark():
              import os
  
              os.kill(os.getpid(), 9)
          return x
  
      @ray.remote
      def average(x):
          return np.mean(x)
  
      x = large_input.options(
          **workflow.options(checkpoint=checkpoint)
      ).bind()
      y = identity.options(
          **workflow.options(checkpoint=checkpoint)
      ).bind(x)
      return workflow.continuation(average.bind(y))
  
file_path: ray/python/ray/workflow/tests/test_checkpoint_2.py
imports: import ray
  import time
  import pytest
  from ray.tests.conftest import *
  import numpy
  from ray import workflow
  from ray.workflow.tests import utils
label_desc: Use image node_id 1 for calling a global function with example usage: checkpoint_dag(checkpoint) and returns: workflow, np, x, np