code: def create_window_func(window_type, window_size):
      if window_type == "hanning":
          return np.hanning(window_size + 1)[:-1]
      elif window_type == "hamming":
          return np.hamming(window_size + 1)[:-1]
      elif window_type == "rectangular" or window_type is None:
          return np.ones(window_size)
  
file_path: nnabla/python/test/function/test_stft.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  import librosa
  from nbla_test_utils import list_context
label_desc: Use image node_id 1 for calling a global function with example usage: create_window_func(window_type, window_size) and returns: np, np, np