code: def validate(runtime_env_dict: dict) -> str:
      return "success"
  
imports: import pytest
  import os
  import sys
  import ray
  import ray.cluster_utils
  from ray._private.test_utils import get_other_nodes, wait_for_condition, is_placement_group_removed, placement_group_assert_no_leak
  from ray._raylet import PlacementGroupID
  from ray.util.placement_group import PlacementGroup
  from ray.util.scheduling_strategies import PlacementGroupSchedulingStrategy
  from ray.util.client.ray_client_helpers import connect_to_client_or_not
  from ray._private.runtime_env.context import RuntimeEnvContext
  from ray._private.runtime_env.plugin import RuntimeEnvPlugin
label_desc: Use image node_id 1 for calling the MockWorkerStartupSlowlyPlugin obj's underlying member method code with example usage: obj.validate(runtime_env_dict) and returns: str