class_docstr: DenStream Micro-cluster class
code: def calc_center(self, timestamp):
      ff = self.fading_function(timestamp - self.last_edit_time)
      weight = self._weight(ff)
      center = {
          key: (ff * val) / weight
          for key, val in self.linear_sum.items()
      }
      return center
  
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 5 for calling the DenStreamMicroCluster obj's underlying member method code with example usage: obj.calc_center(timestamp) and returns: center