code: def test_async_error_callback(self):
      p = self.Pool(1)
      scratchpad = [None]
  
      def errback(exc):
          scratchpad[0] = exc
  
      res = p.apply_async(raising, error_callback=errback)
      p.close()
      p.join()
      self.assertRaises(KeyError, res.get)
      self.assertTrue(scratchpad[0])
      self.assertIsInstance(scratchpad[0], KeyError)
  
imports: from mpi4py import MPI
  import mpi4py.util.pool
  import concurrent.futures
  import itertools
  import functools
  import warnings
  import unittest
  import time
  import sys
  import os
label_desc: Use image node_id 19 for calling the BaseTestPool obj's underlying member method code with example usage: obj.test_async_error_callback() without return types