class_docstr: Standard Absolute Deviation (SAD).
  
  SAD is the model that calculates the anomaly score by using the deviation from the mean/median, divided by the
  standard deviation of all the points seen within the data stream. The idea of this model is based on
  the $3 \times \sigma$ rule described in [^1].
  
  This implementation is adapted from the [implementation](https://github.com/selimfirat/pysad/blob/master/pysad/models/standard_absolute_deviation.py)
  within PySAD (Python Streaming Anomaly Detection) [^2].
  
  As a univariate anomaly detection algorithm, this implementation is adapted to `River` in a similar way as that of
  the `GaussianScorer` algorithm, with the variable taken into the account at the learning phase and scoring phase
  under variable `y`, ignoring `x`.
  
  Parameters
  ----------
  sub_stat
      The statistic to be subtracted, then divided by the standard deviation for scoring.
      Defaults to `stats.Mean()`.
  
  References
  ----------
  [^1]: Hochenbaum, J., Vallis, O.S., Kejariwal, A., 2017. Automatic Anomaly Detection in the Cloud Via
  Statistical Learning. https://doi.org/10.48550/ARXIV.1704.07706.
  [^2]: Yilmaz, S.F., Kozat, S.S., 2020. PySAD: A Streaming Anomaly Detection Framework in Python.
  https://doi.org/10.48550/ARXIV.2009.02572.
  
  Examples
  --------
  
  >>> import random
  >>> from river import anomaly
  >>> from river import stats
  >>> from river import stream
  
  >>> rng = random.Random(42)
  
  >>> model = anomaly.StandardAbsoluteDeviation(sub_stat=stats.Mean())
  
  >>> for _ in range(150):
  ...     y = rng.gauss(0, 1)
  ...     model.learn_one(None, y)
  
  >>> model.score_one(None, 2)
  2.057...
  
  >>> model.score_one(None, 0)
  0.084...
  
  >>> model.score_one(None, 1)
  0.986...
code: def score_one(self, x, y):
      score = (y - self.sub_stat.get()) / (
          self.variance.get() ** 0.5 + 1e-10
      )
  
      return abs(score)
  
imports: from __future__ import annotations
  from river import anomaly, stats
label_desc: Use image node_id 3 for calling the StandardAbsoluteDeviation obj's underlying member method code with example usage: obj.score_one(x, y) and returns: abs