code: def __init__(
      self,
      source_desc,
      batch,
      prefetch_queue_depth,
      bytes_per_sample_hint,
  ):
      self.source_desc = source_desc
      self.batch = batch
      self.prefetch_queue_depth = prefetch_queue_depth
      self.bytes_per_sample_hint = bytes_per_sample_hint
  
imports: from nvidia.dali._multiproc.pool import WorkerPool
  from nvidia.dali._multiproc.messages import TaskArgs, SampleRange
  from contextlib import closing
  from nvidia.dali._utils.external_source_impl import get_callback_from_source
  from nvidia.dali.types import SampleInfo
  from functools import wraps
  import numpy
  import os
  from nose.tools import with_setup
  from nose_utils import raises
  from test_pool_utils import capture_processes, setup_function, teardown_function
label_desc: Use image node_id 1 to create a new MockGroup object  with example: obj = MockGroup(source_desc, batch, prefetch_queue_depth, bytes_per_sample_hint)