class_docstr: Micro-cluster class.
code: def _quantile(self, z):
      return math.sqrt(2) * self.inverse_error(2 * z - 1)
  
imports: from __future__ import annotations
  import math
  from collections import defaultdict
  from river import base, cluster, stats, utils
label_desc: Use image node_id 8 for calling the CluStreamMicroCluster obj's underlying member method code with example usage: obj._quantile(z) and returns: unknown