code: def apply_cmvn(feats, mean, variance, epsilon=1e-9):
      """TF: apply CMVN on feature"""
      return (feats - mean) * tf.rsqrt(variance + epsilon)
  
file_path: delta/delta/utils/cmvn.py
imports: import numpy
  import delta.compat
  from tensorflow.python.keras import backend
label_desc: Use image node_id 5 for calling a global function with example usage: apply_cmvn(feats, mean, variance, epsilon) and returns: unknown