code: def _test_pipe():
      def get_tensor(si):
          return np.arange(
              si.idx_in_epoch,
              si.idx_in_epoch + shape[0],
              dtype=np.int32,
          )
  
      inp = fn.external_source(get_tensor, batch=False)
      return inp.gpu()
  
file_path: DALI/dali/test/python/test_copy_to_external_torch.py
imports: import ctypes
  import numpy
  import nvidia.dali.fn
  import torch
  from nvidia.dali import pipeline_def
  from nvidia.dali import types
  from nvidia.dali.backend import TensorListGPU
label_desc: Use image node_id 1 for calling a global function with example usage: _test_pipe() and returns: inp, np