code: def _init_env_vars(world_rank: int, world_size: int, node_id: str):
      """Initialize Horovod environment variables."""
      os.environ["HOROVOD_HOSTNAME"] = node_id
      os.environ["HOROVOD_RANK"] = str(world_rank)
      os.environ["HOROVOD_SIZE"] = str(world_size)
  
imports: import os
  from dataclasses import dataclass
  from typing import Optional, Set
  from horovod.ray.runner import Coordinator
  from horovod.ray.utils import detect_nics, nics_to_env_var
  from horovod.runner.common.util import secret, timeout
  import ray
  from ray.train._internal.utils import update_env_vars
  from ray.train._internal.worker_group import Worker, WorkerGroup
  from ray.train.backend import Backend, BackendConfig
  from ray.util import PublicAPI
label_desc: Use image node_id 1 for calling a global function with example usage: _init_env_vars(world_rank, world_size, node_id) without return types