code: def hann_win(n):
      hann = np.ones([n], dtype=np.float32)
      a = 2.0 * math.pi / n
      for t in range(n):
          phase = a * (t + 0.5)
          hann[t] = 0.5 * (1.0 - math.cos(phase))
      return hann
  
imports: from nvidia.dali.pipeline import Pipeline
  import nvidia.dali.ops
  import nvidia.dali.types
  import nvidia.dali
  import numpy
  from functools import partial
  from test_utils import get_files
  from test_utils import compare_pipelines
  from test_utils import RandomDataIterator
  from test_utils import ConstantDataIterator
  import librosa
  import math
label_desc: Use image node_id 1 for calling a global function with example usage: hann_win(n) and returns: hann