code: def test_call_sync_vector_env():
      env_fns = [
          make_env("CartPole-v1", i, render_mode="rgb_array_list")
          for i in range(4)
      ]
  
      env = SyncVectorEnv(env_fns)
      _ = env.reset()
      images = env.call("render")
      gravity = env.call("gravity")
  
      env.close()
  
      assert isinstance(images, tuple)
      assert len(images) == 4
      for i in range(4):
          assert len(images[i]) == 1
          assert isinstance(images[i][0], np.ndarray)
  
      assert isinstance(gravity, tuple)
      assert len(gravity) == 4
      for i in range(4):
          assert isinstance(gravity[i], float)
          assert gravity[i] == 9.8
  
file_path: gym/tests/vector/test_sync_vector_env.py
imports: import numpy
  import pytest
  from gym.envs.registration import EnvSpec
  from gym.spaces import Box, Discrete, MultiDiscrete, Tuple
  from gym.vector.sync_vector_env import SyncVectorEnv
  from tests.envs.utils import all_testing_env_specs
  from tests.vector.utils import CustomSpace, assert_rng_equal, make_custom_space_env, make_env
label_desc: Use image node_id 4 for calling a global function with example usage: test_call_sync_vector_env() without return types