code: def engine():
      return SequentialExecutionEngine(max_model_count=30)
  
imports: from __future__ import annotations
  import pytest
  import nni
  from nni.mutable import *
  from nni.nas.evaluator import FunctionalEvaluator
  from nni.nas.execution import SequentialExecutionEngine
  from nni.nas.space import *
  from nni.nas.strategy import GridSearch, Random, RegularizedEvolution, PolicyBasedRL
  import torch
  from torch import nn
  from tianshou.policy import A2CPolicy
  from tianshou.data import to_torch
label_desc: Use image node_id 3 for calling a global function with example usage: engine() and returns: SequentialExecutionEngine