code: def __init__(
      self,
      device,
      batch_size,
      iterator,
      axis,
      nfft,
      num_threads=1,
      device_id=0,
  ):
      super(PowerSpectrumNumpyPipeline, self).__init__(
          batch_size,
          num_threads,
          device_id,
          seed=12345,
          exec_async=False,
          exec_pipelined=False,
      )
      self.device = "cpu"
      self.iterator = iterator
      self.inputs = ops.ExternalSource()
  
      function = partial(power_spectrum_numpy, nfft, axis)
      self.power_spectrum = ops.PythonFunction(function=function)
  
file_path: DALI/dali/test/python/operator_1/test_power_spectrum.py
imports: from nvidia.dali.pipeline import Pipeline
  import nvidia.dali.ops
  import numpy
  from functools import partial
  from test_utils import compare_pipelines
  from test_utils import RandomDataIterator
label_desc: Use image node_id 1 to create a new PowerSpectrumNumpyPipeline object from inherited base classes: Pipeline with example: obj = PowerSpectrumNumpyPipeline(device, batch_size, iterator, axis, nfft, num_threads, device_id)