class_docstr: Micro-cluster class.
code: def __iadd__(self, other: CluStreamMicroCluster):
      self.var_time += other.var_time
      self.var_x = {
          k: self.var_x[k] + other.var_x.get(k, stats.Var())
          for k in self.var_x
      }
      return self
  
imports: from __future__ import annotations
  import math
  from collections import defaultdict
  from river import base, cluster, stats, utils
label_desc: Use image node_id 10 for calling the CluStreamMicroCluster obj's underlying member method code with example usage: obj.__iadd__(other) and returns: self