code: def test_subproc_start_method():
      start_methods = [None]
      # Only test thread-safe methods. Others may deadlock tests! (gh/428)
      # safe_methods = {'forkserver', 'spawn'}
      safe_methods = {"spawn"}
      available_methods = multiprocessing.get_all_start_methods()
      start_methods += list(
          safe_methods.intersection(available_methods)
      )
      space = gym.spaces.Discrete(2)
  
      def obs_assert(obs):
          return check_vecenv_obs(obs, space)
  
      for start_method in start_methods:
          vec_env_class = functools.partial(
              SubprocVecEnv, start_method=start_method
          )
          check_vecenv_spaces(vec_env_class, space, obs_assert)
  
      with pytest.raises(
          ValueError, match="cannot find context for 'illegal_method'"
      ):
          vec_env_class = functools.partial(
              SubprocVecEnv, start_method="illegal_method"
          )
          check_vecenv_spaces(vec_env_class, space, obs_assert)
  
imports: import collections
  import functools
  import itertools
  import multiprocessing
  import pytest
  import gym
  import numpy
  from stable_baselines.common.vec_env import DummyVecEnv, SubprocVecEnv, VecNormalize, VecFrameStack
label_desc: Use image node_id 8 for calling a global function with example usage: test_subproc_start_method() and returns: check_vecenv_obs