code: def get_randn_test(sample_rate, duration):
      """Create a random noise test stimulus"""
      n_samples = int(duration * sample_rate)
      samples = np.random.randn(n_samples)
      return samples.astype(np.float32)
  
imports: import numpy
  import pytest
  import scipy
  import scipy.signal
  from audiomentations import BandPassFilter, BandStopFilter, HighPassFilter, LowPassFilter, PeakingFilter, LowShelfFilter, HighShelfFilter
label_desc: Use image node_id 2 for calling a global function with example usage: get_randn_test(sample_rate, duration) and returns: samples