code: def test_cross_device():
      if cp.cuda.runtime.getDeviceCount() > 1:
          for src in [0, 1]:
              for dst in [0, 1]:
                  for use_dali_tensor in [True, False]:
                      yield _test_cross_device, src, dst, use_dali_tensor
  
file_path: DALI/dali/test/python/test_external_source_cupy.py
imports: from nose.plugins.attrib import attr
  from test_external_source_impl import *
  from test_external_source_impl import use_cupy
  from test_utils import check_output, check_output_pattern
  import nvidia.dali
  from nvidia.dali import Pipeline, pipeline_def
  import nvidia.dali.fn
  from nvidia.dali.tensors import TensorGPU
  import numpy
  import cupy
label_desc: Use image node_id 4 for calling a global function with example usage: test_cross_device() without return types