code: def simple_pipeline():
      jpegs, labels = fn.external_source(
          source=cb, num_outputs=2, parallel=True, batch=False
      )
      images = fn.decoders.image(jpegs, device="cpu")
      return images, labels
  
file_path: DALI/dali/test/python/test_external_source_parallel_garbage_collection_order.py
imports: import os
  import nvidia.dali.fn
  from nvidia.dali import pipeline_def
  from test_utils import get_dali_extra_path
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: simple_pipeline() and returns: images,  labels