code: def load_cmvn(path):
      """load mean and variance from cmvn.npy,
      then convert to TF Tensor
      """
      # [1, nbins, nchannels]
      mean, variance = np.load(path)
      # [1, 1, nbins, nchannels]
      mean = np.expand_dims(mean, axis=0)
      variance = np.expand_dims(variance, axis=0)
      mean = tf.convert_to_tensor(
          mean, dtype=tf.float32, name="cmvn_mean"
      )
      variance = tf.convert_to_tensor(
          variance, dtype=tf.float32, name="cmvn_variance"
      )
      return mean, variance
  
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 4 for calling a global function with example usage: load_cmvn(path) and returns: mean,  variance