code: def map_blocking(fn, collection):
      return ray.get([fn(w) for w in collection])
  
file_path: horovod/horovod/ray/utils.py
imports: from typing import List, Optional, Callable, Any, Dict
  from contextlib import contextmanager
  import ray
  from horovod.runner.driver import driver_service
  from horovod.ray.driver_service import _driver_fn
  from horovod.runner.util import network
label_desc: Use image node_id 4 for calling a global function with example usage: map_blocking(fn, collection) and returns: ray