code: def rate_limited_imap(f, l):
      """A threaded imap that does not produce elements faster than they
      are consumed"""
      pool = ThreadPool(1)
      res = None
      for i in l:
          res_next = pool.apply_async(f, (i,))
          if res:
              yield res.get()
          res = res_next
      yield res.get()
  
imports: from __future__ import print_function
  import numpy
  import time
  import os
  import sys
  import faiss
  import re
  from multiprocessing.pool import ThreadPool
  from datasets import ivecs_read
label_desc: Use image node_id 4 for calling a global function with example usage: rate_limited_imap(f, l) without return types