class_docstr: A learnable transform that rescales the values of a time series to have
  zero mean and unit variance.
code: def __init__(
      self,
      bias=None,
      scale=None,
      normalize_bias=True,
      normalize_scale=True,
  ):
      super().__init__(bias, scale, normalize_bias, normalize_scale)
  
imports: from collections import OrderedDict
  import logging
  from typing import Iterable, Mapping
  import numpy
  import pandas
  import scipy.special
  import scipy.stats
  from sklearn.preprocessing import StandardScaler
  from merlion.transform.base import InvertibleTransformBase, TransformBase
  from merlion.utils import UnivariateTimeSeries, TimeSeries
label_desc: Use image node_id 1 to create a new MeanVarNormalize object from inherited base classes: Rescale with example: obj = MeanVarNormalize(bias, scale, normalize_bias, normalize_scale)