class_docstr: DenStream Micro-cluster class
code: def calc_radius(self, timestamp):
      ff = self.fading_function(timestamp - self.last_edit_time)
      weight = self._weight(ff)
      norm_cf1, norm_cf2 = self.calc_norm_cf1_cf2(ff)
      diff = (norm_cf2 / weight) - ((norm_cf1 / weight) ** 2)
      radius = math.sqrt(diff) if diff > 0 else 0
      return radius
  
imports: from __future__ import annotations
  import copy
  import math
  from abc import ABCMeta
  from collections import defaultdict, deque
  from river import base, utils
label_desc: Use image node_id 6 for calling the DenStreamMicroCluster obj's underlying member method code with example usage: obj.calc_radius(timestamp) and returns: radius