code: def _wait_file_available_on_dbfs(store, url_list):
      """
      On databricks runtime, Waiting about DATABRICKS_FILE_AVAILABILITY_WAIT_TIMEOUT_SECS seconds
      (default 30 seconds) to make sure all files are available for reading.
      This is because Databricks filesystem backend storage such as S3 which only providing
      eventually consistency.
      """
      # Import LocalStore here to avoid circular import
      from horovod.spark.common.store import LocalStore
  
      if isinstance(store, LocalStore):
          return
  
      if not is_databricks():
          return
  
      def wait_for_file(path):
          end_time = (
              time.time()
              + _DATABRICKS_FILE_AVAILABILITY_WAIT_TIMEOUT_SECS
          )
          while time.time() < end_time:
              if store.exists(path):
                  return True
              time.sleep(
                  _DATABRICKS_FILE_AVAILABILITY_CHECK_INTERVAL_SECS
              )
          return False
  
      if len(url_list) == 0:
          raise ValueError("Input url_list argument is empty.")
  
      pool = ThreadPool(min(len(url_list), 64))
      try:
          results = pool.map(wait_for_file, url_list)
          failed_list = [
              url
              for url, result in zip(url_list, results)
              if not result
          ]
          if failed_list:
              raise TimeoutError(
                  "Timeout while waiting for all files to appear at urls {failed_list}.".format(
                      failed_list=",".join(failed_list)
                  )
              )
      finally:
          pool.close()
          pool.join()
  
imports: import horovod.spark.common._namedtuple_fix
  import contextlib
  import os
  import time
  from multiprocessing.pool import ThreadPool
  import pyarrow
  import numpy
  import pyspark.sql.functions
  from pyspark.ml.linalg import DenseVector, SparseVector, Vector, VectorUDT
  from pyspark.sql.types import ArrayType, BinaryType, BooleanType, FloatType, DoubleType, IntegerType, LongType, NullType, StringType
  from pyspark.sql import SparkSession
  from horovod.runner.common.util import codec, host_hash
  from horovod.spark.common import cache, constants
label_desc: Use image node_id 17 for calling a global function with example usage: _wait_file_available_on_dbfs(store, url_list) and returns: False, True