code: def _standard(self, data):
      return (data - np.mean(data)) / np.std(data)
  
file_path: nlpaug/nlpaug/model/audio/normalization.py
imports: import numpy
  from nlpaug.model.audio import Audio
label_desc: Use image node_id 3 for calling the Normalization obj's underlying member method code with example usage: obj._standard(data) and returns: unknown