code: def test_beat_no_input():
      librosa.beat.beat_track(y=None, onset_envelope=None)
  
imports: import os
  import pytest
  from contextlib import nullcontext
  import numpy
  import scipy.stats
  import librosa
  from test_core import files, load
label_desc: Use image node_id 4 for calling a global function with example usage: test_beat_no_input() without return types