code: def test_water_cpu_vs_gpu():
      niter = 3
      for batch_size in [1, 3]:
          for do_mask in [False, True]:
              for dtype in [types.UINT8, types.FLOAT]:
                  yield check_water_cpu_vs_gpu, batch_size, niter, dtype, do_mask
  
imports: import nose_utils
  from nvidia.dali.pipeline import Pipeline
  import nvidia.dali.ops
  import nvidia.dali.fn
  import nvidia.dali.types
  import nvidia.dali
  import numpy
  import os
  import cv2
  from test_utils import compare_pipelines
  from test_utils import get_dali_extra_path
label_desc: Use image node_id 3 for calling a global function with example usage: test_water_cpu_vs_gpu() without return types