code: def test_cupy_kernel():
      validate_cpu_vs_gpu(square_diff_kernel, square_diff)
  
file_path: DALI/dali/test/python/test_gpu_python_function_operator.py
imports: import cupy
  from nvidia.dali.pipeline import Pipeline
  import nvidia.dali.ops
  import nvidia.dali.types
  import numpy
  import test_utils
  import random
  import os
label_desc: Use image node_id 6 for calling a global function with example usage: test_cupy_kernel() without return types