code: def train_func(self):
      # training code
      result = {"mean_accuracy": "my_accuracy"}
      if detect_instance_preemption():
          result.update(should_checkpoint=True)
      return result
  
imports: import os
  import torch
  from torch import nn
  from ray import train, tune
  import random
  import os
  import tempfile
  from ray import train, tune
  from ray.train import Checkpoint
label_desc: Use image node_id 2 for calling a global function with example usage: train_func() and returns: result