code: def validate_test_cluster_env(test: Test) -> Optional[str]:
      if test.is_byod_cluster():
          """
          BYOD clusters are not validated because they do not need cluster environment
          """
          return None
  
      from ray_release.template import get_cluster_env_path
  
      cluster_env_path = get_cluster_env_path(test)
  
      if not os.path.exists(cluster_env_path):
          raise ReleaseTestConfigError(
              f"Cannot load yaml template from {cluster_env_path}: Path not found."
          )
  
      return None
  
imports: import copy
  import json
  import os
  import re
  from typing import Dict, List, Optional, Tuple, Any
  import jsonschema
  import yaml
  from ray_release.test import Test, TestDefinition
  from ray_release.anyscale_util import find_cloud_by_name
  from ray_release.bazel import bazel_runfile
  from ray_release.exception import ReleaseTestCLIError, ReleaseTestConfigError
  from ray_release.logger import logger
  from ray_release.util import DeferredEnvVar, deep_update
label_desc: Use image node_id 9 for calling a global function with example usage: validate_test_cluster_env(test) and returns: None, None