class_docstr: DenStream Micro-cluster class
code: def merge(self, cluster):
      self.N += cluster.N
      for key in cluster.linear_sum.keys():
          try:
              self.linear_sum[key] += cluster.linear_sum[key]
              self.squared_sum[key] += cluster.squared_sum[key]
          except KeyError:
              self.linear_sum[key] = cluster.linear_sum[key]
              self.squared_sum[key] = cluster.squared_sum[key]
      if self.last_edit_time < cluster.creation_time:
          self.last_edit_time = cluster.creation_time
  
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 8 for calling the DenStreamMicroCluster obj's underlying member method code with example usage: obj.merge(cluster) without return types