code: def test_fade():
      """test_fade"""
  
      path = os.path.join(
          os.path.dirname(os.path.abspath(__file__)),
          "test_audio",
          "mono_10khz.wav",
      )
      audio = tfio.audio.decode_wav(
          tf.io.read_file(path), dtype=tf.int16
      )
      assert audio.shape == [5760, 1]
      audio = tf.cast(audio, tf.float32) / 32768.0
  
      audio = audio[2000:4000]
  
      fade_in = 1000
      fade_out = 1500
      for mode in ["linear", "logarithmic", "exponential"]:
          fade = tfio.audio.fade(
              audio, fade_in=fade_in, fade_out=fade_out, mode=mode
          )
  
imports: import os
  import sys
  import pytest
  import numpy
  import tensorflow
  import tensorflow_io
label_desc: Use image node_id 31 for calling a global function with example usage: test_fade() without return types